Indian Railway signaling

Transcription

CHAPTER – I
HISTORY OF RAILWAYS AND EVOLUTION OF SIGNALLING SYSTEM
1
Evolution of Indian Railways:
1.1
The fundamentals of Railway transportation are to move vast traffic carrying goods and
people speedily and with safety on a prepared track that supports and guides the vehicles which
roll along its surface. A railway train must go where the rails lead it to.
The process might have begun accidentally when Babylonians and perhaps their Sumerian
ancestors observed that their two wheeled, animal drawn, carriage gauged out parallel ruts in the
ground path, which they most commonly followed. Greeks made the smooth stone ways for
transporting their heavy material for building monuments. Thus the railway existed even earlier
to evolution of steam engines as long back as 2245 BC i.e. some 4250 years back.
1.2
Horse traction began after introduction of iron rails and lasted beyond 19th century. The
revolution to transport industry came with the evolution of steam engines. Although steam loco
was invented in 1803 but it took innumerable refinements before it could be adopted for reliable
and safe substitute for horse. The story of railways as we perceive to is 180 years old only. A
pair of bullocks hauled traffic on first indigenously financed railways named as Gailwar’s
Baroda State railway (GBSR), which was opened in 1863.
1.3
Idea to connect the then Bombay with Thana with a railway track was conceived by
Chief Engineer, Bombay Government in 1843. Great India Peninsula Railway (GIPR) Company
was incorporated in England by an act of Parliament on 1st August, 1849. The Railway
Company entered into a contract with East India Company on17th August, 1849, accordingly the
Railway Company was to raise capital of ₤ 500,000. The construction of the line from Bombay
to Kalyan started on 31st October, 1850. The first railway line in India covering 34 kilometres
between Boribunder, the then Bombay and Thana was opened on 16th April 1853, barely 28
years after the World’s first train made its initial success run between Stockton and Darlington
in England in 1825. Within one year the line was extended to Kalyan on 1st May, 1854. This was
first railway system in Asia.
1.4
In Eastern sector, first passenger train moved out of Howrah station for Hogly on 15th
August, 1854 covering a distance of 39 kilometres. The railway line was extended by 61
kilometres upto Pundooah on 1st Septmber, 1854 and then further extended upto Raniganj on 3rd
February, 1855. First by 101 kilometres railway line was opened between Veyasarpaudy and
Walajah Road on 1st July 1856 in South. In North first Railway line was laid between Allahabad
and Kanpur, a distance of 192 kilometres on 3rd March, 1859 and then in Amritsar-Atari section
was opened after three years. Hathras Road to Mathura Cantt. section was opened on 19th
October, 1875. Dibrugarh Town to Dinjan section in East was opened on 15th August, 1882.
1.5
During 1854 and 1860, the contract to private companies to built and operate the
railways was made by East India Company or after 1858 by the secretary of State for India, with
the East Indian Railway company, the GIPRS company, the Madras railway company, the
Bombay Baroda and Central India Railway company, the Eastern Bengal railway company, the
1
Great southern of India Railway Company and Calcutta and South Eastern railway company.
Under these contracts the Railway Companies undertook and managed specified lines to which
East India company and later Secretary to State for India agreed to provide land free of cost and
also guaranteed return on capital varying as 5%, 4 ¾%, 4 ½% in different cases according to
market rates prevalent at the time of execution of the contract. The rate of exchange for
remittance of interest was also fixed. Half of any surplus of profits earned was to be used
towards repaying the Government any sums by which it had been called upon to supplement at
the net earning in any previous period to make good the guaranteed rate of interest, and the
remainder was to belong to the share holders. The terms on which the contracts were given were
considered in India as well as in England as unduly generous for the British Investors.
1.6
Government ownership of Railways – For several years after 1869, the capital
expenditure on Railways was mainly incurred direct by the Government and no fresh contracts
were made with guaranteed companies except for small extensions. However, consequent on
severe famine in 1878, the necessity of rapid extension of the railway system was felt by
Government and it was decided to use private enterprise to the extent possible with such
guarantees as would secure investment of capital without involving Government in financial or
other liabilities of an objectionable nature. On this basis, a number of companies were formed
between 1881 and 1892, and the guarantees which were given to some of these companies were
much more favourable to Government than in the case of companies formed prior to 1869. In
dealing with the guaranteed companies formed before 1869 and with those formed in 1881 and
subsequently, Government’s endeavour was to secure, at the earliest possible date, wherever it
had the right to terminate the original contract after a specific period, either more favourable
terms under fresh contracts or ownership by purchasing the company under the terms of the
contract. Thus under the terms negotiated with the various guaranteed Railway Companies, the
dates of termination of contracts fell between 1879 and 1907
1.7
Company management of Government Railways –The Eastern Bengal, the Oudh and
Rohilkhand, the Sind-Punjab and Delhi, and the Southern Punjab Railways, the last two forming
part of the North Western Railway, Company Railways were transferred to Government
management after purchase. The management of some of the other purchased lines was,
however, entrusted to working companies constituted under contracts which determined the
relationship between the Government and the Working Companies generally.
The contracts with the working companies were terminated in due course and the management
of the companies was taken over directly by the Government on the dates given below:
Name of the Railway
1) The East Indian Railway
2) The Great Indian Peninsula Railway
3) The Bombay Baroda and Central Indian Railway
4) The Assam Bengal Railway
5) Oudh and Tirhut Railway
6) The Madras and Southern Mahratta Railway
7) The South Indian Railway
8) The Bengal Nagpur Railway
2
Date of taking over by Government
1st January, 1925
1st July, 1925
1st January, 1942
1st January, 1942
1st January, 1943
1st April, 1944
1st April, 1944
1st October, 1944
1.8
Partition of country affecting railways– With the attainment of independence and
partition of the country on the 15th August, 1947, two of the exiting Railway systems (viz.,
North Western Railway in the west and the Bengal Assam Railway in the East), Which fell into
both the territories, had to be divided. The portions of these systems falling in India were either
partly added to the other existing lines or partly formed into separates units, thus the Eastern
Punjab Railway and the Assam Railway Administration came into being as separate units
although they were not considered economical, efficient and self- sufficient systems. An
administrative re-organisation with a view to securing both efficiency in operation and economy
in management, therefore, became a compelling necessity.
1.9
Taking over of the ex-States Railways – As a result of integration of the Indian State
into a small number of sizeable units after their incorporation in the Union, and the further
integration with the Union of their federal functions, the railways owned and managed by those
States came under the control of the Central Government in addition to those which were
already being worked by the Indian Railways and were later merged into the contiguous Indian
Railway System. These were Gaekwar’s Baroda State Railway, 736 miles, taken over on 1st
August, 1949 was merged with the Bombay and Baroda and Central Indian Railway System
from the date taking over; Bikaner State Railway, 883 miles; Cutch State Railway, 72 miles;
Dholpur State Railway, 56 miles; Jaipur State Railway,253 miles; Jodhpur State Railway, 807
miles; Mysore State Railway, 2 miles; Nizam’s State Railway, 1,396 miles; Rajasthan
Railway,179 miles; Saurashtra Railway, 1,274 miles; Scindian State Railway, 294 miles, were
taken over on 1st April, 1950.
1.10
Re-organisation of Railways in 1951 - 1952– The revision of financial convention,
with effect from 1st April, 1950 regulating relationship between general and the Railway
finances, along with the integration of all the railways, compelled reorganisation of the entire
Railway system resulting in creation of six Zonal Administrative units viz. 1.) Southern Railway
with 9867 route kilometres formed on 14th April 1951 merging Madras and Southern Railway
4732 kilometres, South Indian Railways, 3782 kilometres and Mysore State Railways, 1173
kilometres; 2) Central Railway with 8739 route kilometres, formed on 5th November, 1951
merging Great Indian Penisula Railway, 5823 kilometres, Nizam’s State Railway, 2353
kilometres, Dholpur State Railway, 90 kilometres and Scindia State Railway, 473 kilometres; 3)
Western railway with ,8793 route kilometres merging Bombay Baroda and Central India
Railway except Delhi – Rewari- Fazilka and Kanpur – Achnera sections, 5670 kilometres,
Surashtra Railway, 2195 kilometres, Jaipur State Railway, 469 kilometres, Rajsthan railway
317 kilometres, Cutch State Railway, 116 kilometres and Marwar- Phulad section of Jodhpur
Railway,26 kilometres ; 4) Eastern Railway with 9123 route kilometres formed on 14th April,
1952 merging Bengal Ngpur Railway 5455 kilometres and East Indian railway except some
portion merged in Northern railway, 3668 kilometres; 5) Northern Railway with 9672
kilometres formed on 14th April, 1952 merging East Punjab Railway, 3083 kilometres, Bikaner
State Railway, 1422 kilometres, Jodhpur Railway except Marwar- Phulad section, 1280
kilometres, Moradabad, Lucknow and Allahabad Divisions of East Indian Railway, 3383
kilometres and Delhi – Rewari – Fazilka section of Bombay, Baroda and Central India
Railway; and 6) North Eastern railway with 7675 kilometres formed on 14th April, 1952 merging
Oudh Tirhut Railway, 4413 kilometres, Assam Railway, 2857 kilometres and Kanpur – Achnera
section of Bombay, Baroda and Central India railway 405 kilometres.
3
1.11
Re-organisation of Railways in 1955 – 1966: These Railways were reorganised need
based again in 1955-1966. Eastern Railway was split to form Eastern Railway and South Eastern
Railway on 1st August, 1955; North Eastern Railway was bifurcated to form North Frontier
railway and North Eastern railway on 15th January, 1958; A portion of Southern Railway and
Central Railway was taken out to form South Central Railway on 2nd October, 1966. With this
six zones were reorganised into nine zones by 1966.
1.12
Re-organisation of Railways in 2001 and 2003: Two new zones viz. North Western
Railway with its headquarters as Jaipur and East Central Railway with its headquarter as
Hajipur, were created on 01.10.2001 and further five more Zonal railways viz. North Central
Railway with its headquarter as Allahabad, South East Central Railway with its headquarter as
Bilaspur, East Coast Railway with its headquarter as Bhubaneshwar, South Western Railway
with its headquarter as Hubly and West Central Railway with its headquarter as Jabalpur were
created on 01.4.2003, by carving out of existing railways. With this sixteen Zonal railways exist
as on date. In addition RDSO was given independent status retaining its headquarter as
Lucknow.
1.13
Indian Railway act 1890: In order to regulate working and to provide suitable
machinery for working of railway system, The Indian Railway Act, 1890 was enacted on 21st
March, 1890 to take effect from 1st May, 1890. The act lays down the statute regarding
construction and maintenance of work, opening of railways, responsibilities of Railway
administration as carriers, railway accidents and a number of allied to railway working.
With the constitution of Railway Board for controlling the administration of railways in India,
Railway Board Act, 1905 was passed on 22nd March, 1905, to invest certain powers and
functions with the Railway Board, under Indian Railway Act, 1890.
2
2.1
Evolution of Railway Signalling system:
The present shape of railway signalling has
evolved after covering long passage from
train lead by a horseman with a red flag in
his hand and a lighted candle placed on the
table of Station Master, first signal ever used
at Hartlepool in England. The policeman at
the back of horse called as Bobies used to
maintain a time interval between the trains.
2.2
During 1829, in USA hand signals were used in
the day and lighted lantern in the night in Baltimore Ohio Rail Road. Thereafter bell shaped peacock signals and ball signals were
devised followed by Kite signals. Marine telescopes were used by flagmen to observe
signals and to repeat them to adjoining station. Block signalling was a crucial
development for railway signal and interlocking. Willium F. Cooke and Charles Wheat
Stone, people who developed Railway telegraph, developed Cooke & Wheat stone
needle graph in 1837. In 1838, Disk and crossbar signal was used on Great Western
Railway as suggested by Brunel, a Permanent Way Engineer of British Rail Road.
4
2.3
In 1840 red metal disk, four feet diameter with word danger painted on it was used on
British Railway. Coming to present day signalling system first were semaphore signals.
Charles Hutton erected first semaphore signal at Newcross England, in 1841.The ‘V’
notch in the tail of signal was introduced by John Sexy in 1872, to indicate signal to be
permissive. Somersault Semaphore was introduced by Edward French in 1877. During
the intervening period continuous development in the shape of spectacles and fixing of
lenses was done by British Rail Road Engineers James Deakin in 1843, James Stevens
in 1847, Boakes & Reilly in 1853, John Saxby in 1854 and by Rowe in 1865.
2.4
The first mechanical interlocking was installed at Bricklayers arms Junction in England
by C.H. Georgy with levers for points and stirrups for signals, in 1843, which was
improvised by Stevens in 1847. Further developments were done by Douglas Galton,
Col Yolland, John Saxby & Austin Chambers Signal Engineers in U.K. and Ashbel
Welch signal engineer in U.S. Operation of trains using signals only without train order
was first demonstrated by Eastern Rail Road Company in 1843, through Salem–
Massachutssets Tunnel. This system went through further developments and became
train traffic control.
2.5
George Boole developed his algebra of logics named after him as Boolien’s algebra, in
1847, which was widely used to design electrical interlocking circuits. Single stroke bell
system was developed by Charles Vincent Walker in 1851. In 1858, Block System
based on space interval was developed in England. Tyer developed a train indicator in
1861. In 1863 a banner signal was used in Philadelphia Railway. A rotating disk painted
half red and half white was also used during this period. In United States Ashbel Walch
introduced manual block system with space interval, for the first time in 1863. Charles
Ernest Spangnoletti developed disk block instrument in 1864. Strowley in1866 patented
in England the wedge system for facing point tongues. Lock bar to prevent operation of
points under wheel was introduced by Liversey, Edwards & Jeffereys in 1868. Saxby in
collaboration with Liversey and his partners introduced Facing point plunger lock in
1870. Schrender, Spiear, Cohman, Hanton, and others in U.S. and Schnable & Hunning
of Germany used hydraulic pressure for operating signals, in 1871. Harve Talden &
Guerben developed it for operation of points and signals, in 1881. Electromagnetic
control came in1882 at Board Brock in New Jersey, U.S.A.
2.6
Siding control was introduced by James Annet in 1876. First power interlocking was
installed in U.S. in 1876 under patent of Pratt & Burr, Tylor’s electric interlocking
in1889, and Ramsey & Weir’s in 1888. In 1876, Sykes introduced lock and block
system at St. Pauls station in London. In 1878 Edward Tyer introduced tablet apparatus.
The Tyer’s system was modified by Webb & Thompson in1888. Track locking was
devised by Lackson in 1880. First electromechanical signal- interlocking was installed
by Sykes in 1883 at Victoria Terminal in England. Absolute Block System was made
compulsory in Britain for all passenger trains in 1889 by an act of Parliament. Direct
current motor operation of signals was developed by Ramsay, Weir Latting and others
in 1890. Sykes & Wyles after the Aburmuile head on collision introduced electrical
interlocking between Starter signal and the corresponding Block Instrument for the first
time in Farnham London and South Western Railway in 1893. Telephone was used for
5
the first time for train order in 1897 in the Smith Fork branch of Pennsylvania Rail
Road.
2.7
Colour light signals were first used in United States in 1904. The visibility of this signal
was 150 Mts only. These signals were initially meant for tunnels first having been
installed in East Boston tunnel of Boston Elevated Railway. The visibility of these
signals was improved to 450 Mts. In 1912 and to 1050 Mts. range in 1914. Position light
signals were developed in 1915. First colour light signal were used in Britain at
Liverpool cross Road Railway in 1920 while first search light signals of 1350 Mts.
visibility range were developed in the same year. Double wire signalling was developed
around 1920 in Germany. Colour light signals with two coloured lamps were introduced
in 1921.A.F. Bound introduced speed signalling at Mir field in England. Automatic
signalling with semaphore signals was developed by A.H. Johnson in England in 1926.
LMG Ferreia & R.J. Insell of Great Western Railway introduced route working with
miniature levers.
2.8
The basics thus installed have continued to march forward thereafter changing shape in
the form of Relay interlocking, Route relay interlocking, Block Proving by Axle
counters, change of analogue axle counters to Digital Axle counters, DC track circuits to
multi section digital axle counters, Audio Frequency track circuits, Jeomont Track
circuits etcetera.
2.9
The conventional signals erected by the side of track have gone into the cab of Electric
locomotives. With the fast pace of advancement, it was no more possible to run the
trains followed by a man riding horseback or guided by a lighted candle on the Station
Masters table. The signalling has passed through phase from semaphore via colour light
to cab signalling. The points in the yard operated by solid rod switching over to
operation by electric point machines.
*****
6
CHAPTER-II
INTRODUCTION TO INDIAN RAILWAY SIGNAL ENGINEERING
1
The Railway Signalling System:
Had there been all trains standing, they were the safest. Had there been only one train on one
track, it was still safer, but Indian Railways is spread over about 63,332 route kilometres of
track, about 7000 stations, running about 14300 trains daily carrying about 13 million
passengers and 2 million tonnes of freight every day, necessitating deployment of 1.57 million
people, as during financial year 2006-2007. Such a huge network cannot be managed without
sharing responsibility with mechanisation.
This necessitated the need of signalling system and the need of signals as a means of
communication between men on ground and with the driver of the train now designated as Loco
Pilot running on fixed path.
Before proceeding ahead it is important to understand the basics of Railway structure,
associated terms and rules which govern the design of railway signalling system:
The working of trains is governed by General Rules (GR) of Indian Railways. The signalling
system is designed to comply these rules technically, in consideration of technical feasibility and
financial aspects vis-à-vis manageability of compliance of these General Rules manually versus
mechanisation, depending upon density of traffic and speed of the trains permitted in the section.
The guidelines for technical measures for compliance of these General Rules are given in Signal
Engineering Manual and Railway Opening of Public carriage Rules. The latest General Rules
taken into consideration are as issued in the year 2007 and Signal Engineering Manual
Volume-I, I988 and Volume –II of 2001.
2
2.1
i)
ii)
iii)
iv)
v)
Generally used terms, Stations and signals:
Generally used terms:
Approved special instructions: means special instructions approved of or prescribed
by the Commissioner of Railway Safety.[GR 1.02 (4)]
Special Instructions: Instructions issued from time to time by the authorised officer in
respect to particular cases or special circumstances.[GR 1.02 (53)].
Running Line: the line governed by one or more signals and includes connections, if
any, used by a train when entering or leaving a station or when passing through a station
or between stations. [GR 1.02 (47)].
Running train: a train which has started under an authority to proceed and has not
completed its journey. [GR 1.02 (48)].
Shunting: The movements of a vehicle or vehicles with or without an engine or of any
engine or any other self propelled vehicle, for the purpose of attaching, detaching or
transfer or for any other purpose.[ GR 1.02 (49)].
2.2
Station: Station is that part of track where train traffic is dealt with to stop, despatch,
make trains run-through, perform shunting, loading unloading of goods, watering of coaches,
7
maintenance and many other activities for a goods or passenger train. As per General Rule 1.02.
(51), issued by Indian Railways, the station is defined as “any place on a line of railway at which
traffic is dealt with, or at which an authority to proceed is given under the system of working”.
The station is sectionalised in two parts i.e. Station section and Station limits.
3
Classification of Stations: In the present context, stations are classified with reference
to operational facilities and standard of interlocking.
The speed of the trains in a particular section is broadly guided by the standard of track, the
standard of rolling stock, and the ruling gradient.
The operational facilities at the stations as well as type of interlocking and the system of
signalling at the stations also affects average speed of the section. The electrical/solid state
interlocking operated through central panel reduces operational time by way of eliminating inter
cabin coordination as well as faster operation as compared to interlocking in mechanical lever
frames, or panels in end cabins. The system of colour light signalling also similarly reduces
operation time as compared to semaphore signalling system.
It is pertinent to note that the standard of interlocking at the station does not function as ruling
factor for deciding speed of the section.
3.1
Classification of stations based on operational requirements: [GR 1.03] Stations are
classified as ‘Block Stations’ and ‘Non-Block Stations’.
3.1.1 Block Stations are those stations at which the Loco Pilot must obtain an authority to
proceed under the system of working to enter the block section with his train. The Block station,
under the Absolute Block system consists of three classes viz. class À’, class `B’ and class `C’.
However when any station which cannot be worked under À’, `B’, or `C’ class is termed as
`Special’ class station [GR 1.03]. These stations are characterised by the conditions for granting
line clear under GR 8.02, 8.03 and 8.04 as follows:
i)
ii)
iii)
Class À’ stations: Stations where Line Clear may not be given for a train, unless the
line on which it is intended to receive the train, is clear for at least 400 metres beyond
the Home Signal, or up to the Starter signal;
Class `B’ stations: Stations where Line Clear may be given for a train before the line
has been cleared for the reception of the train within station section; and
Class `C’ stations: The capacity of a section to accommodate trains, if gets saturated
i.e. trains running in a specific section are more than the section can accommodate, the
longer block section is bifurcated by creating a Block Hut or, on a double line section,
an Intermediate Block post, in between. In this way two trains can be run in the section
where only one train was running. This is a small step as an alternative of Automatic
Block Signalling, where more than two trains ca be run by splitting the Block section
into smaller Automatic Block sections.
8
a) Block Hut, is a ‘C’ class station for the purpose of splitting the block working only,
where Line Clear may not be given for a train, unless the whole of the last preceding
train has passed complete at least 400 metres beyond the Home signal, and is
continuing its
journey. This also includes Intermediate Block Post.
b) Intermediate Block Post means a class “C” station on a double line remotely
controlled from the block station in rear.
The Signalling arrangement on an Intermediate Block post is to split a long
block section into two portions each constituting a separate block section
providing an intermediate Block Post.
iv)
Non-Block stations or class `D’ stations: are scheduled stopping stations for specified
trains. These stations are situated between two consecutive block stations, and do not
forms the boundary of any block section. The stations at which there is outlaying siding
are also called as DK station and those where there is no siding, are also called as flag
station.
3.2
Classification of stations based on Standard of Interlocking and;
3.2.1 The Standards of Interlocking: On Indian railways three standards of interlocking
were prescribed prior to introduction of Signal Engineering Manual volume-I 1988. On
introduction of Signal Engineering Manual Volume-I, 1988, these standards were enhanced to
five standards and then subsequently modified to four, restricting maximum speed from
unrestricted as permitted through Signal Engineering Manual in force prior to the introduction of
Signal engineering Manual 1988, to a maximum of 160 Kilometres per hour through Correction
slip No. 6 to SEM 1988 clause 7.131.
i)
ii)
iii)
The standards of interlocking decide maximum permissible speed of the train across the
station. For example maximum permissible speed of the train on which the train can
run-through across a station provided with standard-I interlocking, is 50 Kilometres per
hour. This in turn decides the minimum equipment of signals, point fittings, isolation,
type of signalling system, type of operating system and type of interlocking. These are
chosen in such a way that it is possible to achieve desired level of speed of the train at
and across the station with maximum safety, minimum operation time, minimum level
of human involvement and minimum financial implications, corresponding to the given
speed.
The minimum equipment of signals as provided for any of the standards of interlocking
may by be increased depending upon operational requirements but not to the extent that
it changes the given standard of interlocking.
The classification of standards of interlocking on all Indian railways with reference to
the maximum allowable speed of the trains, minimum equipment required at such
stations as well as other features as prevalent before the introduction of Signal
Engineering Manual 1988, are tabulated below in table number 3.2.1.a:
9
1
Standard :
I
1.1
Allowable speed:
50 kilometre per hour
1.2
Isolation:
It is recommended that main line be isolated but it is not compulsory if, in every case, in which
trains are permitted to run through on non isolated line, all shunting is stopped and no vehicle
which is not attached to an engine or not properly secured by the Station Master in accordance
with approved special instructions, is kept standing on a connected line which is not isolated
from the through line (clause 4.11 & 5.23 of General rule book 2007).
1.3
Signals:
1.3.1
In semaphore signalling system:
1.3.1.1 Outer and Warner to be provided. Provision of starter signal is optional;
1.3.1.2 Warner signal shall be provided for Metre Gauge stations where trains run through, if
considered necessary;
1.3.1.3 All signals shall be operated from an interlocked frame under control of Station
Master.
1.3.1.4 On the section with light traffic the outer signal may be operated from the location
near the facing point ensuring that Outer signal shall not be possible to be taken ‘Off’
unless home signal has been taken ‘Off’.
1.3.1.5 In exceptional cases, under approved special instructions, Warner where provided,
may be operated from the same location as that of outer such that Warner can not be
taken ‘Off’ unless other relevant signals for main line have been taken ‘Off’ and line
clear has been taken in advance
1.3.1.6 In exceptional cases, under approved special instructions two home signals may be
placed on the same post in lieu of bracketed home signal. The top arm shall apply to
main line and the lower one to shall apply to other lines;
1.3.2
In Multiple Aspect Signalling system:
A Distant and a Home signal in each direction.
1.4
Points:
Facing points shall be equipped with:
1.4.1
A key lock of approved type;
1.4.2
A means for locking each switch independently;
1.4.3
A means for preventing the points from being unlocked during the passage of train;
unless the arrangement is such that a key is used to release the signals and can not be
brought back to the points until such signals have been put back to ‘On’ position;
1.4.4
A means for detecting each switch independently by respective signals;
1.4.5
A gauge ties plate where steel sleepers are not provided.
1.5
Interlocking:
1.5.1
Interlocking between points and signals may be carried out by means of key locks
and shall be so arranged that the Station Master can not lower a fixed signal for the
movement of a train unless all facing points falling in the route of the train are
properly set and locked.
1.5.2
If Warner signals are provided the interlocking between the Warner signal and the
points must extend to the trailing points.
1.5.3
Where the interlocking between points and signals is electrically transmitted the
insulation of the line wires used in connections therewith shall be of the same
10
1.5.4
2
2.1
2.2
2.3
2.3.1
2.3.1.1
2.3.1.2
2.3.2
2.4
2.4.1
2.4.2
2.4.3
2.4.4
2.4.5
2.5
2.5.1
3
3.1
3.2
standard as laid down as laid down for installation of block instruments;
Interlocking between points and signals must ensure that no signal can be taken ‘Off’
to admit a train on line that has been fitted with a tarp switch, unless the trap switch
has been closed.
Standard :
II
Allowable speed:
75 KMPH
Isolation:
Required, with the condition that the line on which the train is to run has been
isolated from all other lines by the setting of points or other approved means and
interlocking is such as to maintain this condition during the passage of the train.
(Clause 4.11 of General rule book 2007).
Signals:
Outer, Warner and bracketed home signals must be provided. Provision of starter is
optional;
Taking ‘Off’ of Warner signal shall be dependent upon the receipt of line clear on the
block instrument;
A Distant, a Home and a starter signal in each direction
Points:
Facing points shall be equipped with:
A plunger type facing point lock. If the plunger is hand operated or economical lock
type, its full travel should be detected by relevant signal.
A means for locking each switch independently;
A means for preventing the points from being unlocked during the passage of train;
unless the arrangement is such that a key is used to release the signals and can not be
brought back to the points until such signals have been put back to ‘On’ position;
A gauge tie plate where steel sleepers are not provided.
Interlocking:
The interlocking between points and signals may be direct or indirect. Where indirect
interlocking is used signals shall be operated from a position under the control of the
Station Master, and a key must be provided to enable the Station Master to lock up
the signal frame. The interlocking between points and signals must be carried out
under the same conditions as prescribed for standard – I and must ensure that all
trailing points are correctly set and held in position by the lowering of signal for
movement over them. When points and signals are operated from locations at either
end of the station the interlocking between points and signals must be direct and must
ensure the same conditions as laid down for direct interlocking. The Station Master
must be provided with a control over the Home and Last stop signal.
Standard:
III
Allowable speed:
Unrestricted
Isolation:
Required, with the condition that the line on which the train is to run has been
isolated from all other lines by the setting of points or other approved means and
11
interlocking is such as to maintain this condition during the passage of the train.
(Clause 4.11 of General rule book 2007).
3.3
Signals:
3.3.1
Outer, Warner, Bracketed home signals and Starter signals must be provided while
Advanced starter signals may be provided as and where necessary;
3.3.2
A Distant, a Home and a starter signal in each direction.
3.3
Points:
3.3.1
A plunger type facing point lock;
3.3.2
A means for detecting the full travel of the lock plunger by related signals when the
lock and switches are operated by the same lever. (Operation of lock and switches by
the same lever has since been stopped );
3.3.3
It is desirable that plunger detection may also be provided for independent ly
operated facing point locks.
3.3.4
3.3.5
A means for detecting each switch independently;
3.3.6
A gauge tie plate where steel sleepers are not provided.
3.4
Interlocking:
3.4.1
The interlocking between points and signals must be direct. For this the operation
system of all signalling functions shall be essentially centralised at one place in one
frame or cabinet.
Table 3.2.1.a
Table showing Standards of Interlocking and associated minimum equipment of Signals and
Points before introduction of SEM 1988.
All works after the introduction of Signal engineering Manual 1988 (Volume-I only) have to be
introduced in conformity to Signal Engineering Manual1988 only. The stations are classified as
Standard -I, Standard- II, Standard- III and Standard- IV, with reference to standards of
interlocking paragraph 7.131 of Signal Engineering Manual 1988 read with correction slip No.6.
The maximum speed of the trains and minimum equipment as well as other features at stations
with reference to corresponding standard of interlocking, are tabulated below, as may be seen in
table No. 3.2.1.b:
SN Features
Standard I
Standard II
Standard III
Standard IV
Allowable
Upto 50
Upto 110 KMPH Upto 140
Upto 160
speed
KMPH
KMPH
KMPH
1
Isolation
Required *
Required
Required
Required
2
Signalling
2 Aspect/ Multi 2 Aspect/ Multi
Multi Aspect
Multi Aspect
Aspect
Aspect
3
Double
Not required
Required
Required
Required
Distant
4
Point
Mechanical
Mechanical/
Mechanical/
Electrical
Operation
Electrical
Electrical
5
Point locking Key/Facing
Facing Point
Facing Point
Point machine
Point Lock
Lock / Point
Lock / Point
(Clamp type is
12
6
7
8
Point
detection
Lock
detection
Interlocking
/Hand Plunger
Lock
Mechanical/
Electrical
Not Required
machine
machine
desirable)
Mechanical/
Electrical
Required
Mechanical/
Electrical
Required
Electrical
Key/
Mechanical
Mechanical/
Electrical/
Electronics
1. Mechanical
Interlocking –
Main run through
lines
2. Electrical/
Electronic
interlocking – All
running lines
Mechanical/
Electrical/
Electronics
All running
lines
Electronics
Token/SGE
SGE/Track
circuit #
SGE/Track
circuit #
Not required
Not required
Desirable
9
Track
circuiting to
be done of:
10
Block
Token
working
(min)
Preventing
Not required
signal passing
at danger
11
Not required
Required
All running
lines
* but not compulsory subject to in every case in which trains are permitted to run through on
non isolated line, all shunting shall be stopped and no vehicle which is not attached to an engine
or not properly secured by the Station Master in accordance with approved special instructions,
may be kept standing on a connected line which is not isolated from the through line (Clause
4.11 & 5.23 of General rule book 2007).
Abbreviations used in the tableSGE - The type of double line block instrument;
# At stations where central panel is provided or at high density routes, means for verifying
complete arrival of trains by suitable means shall be required.
Table 3.2.1.b
Table showing Standards of Interlocking and associated minimum equipment of Signals and
Points with the introduction of SEM 1988.
4
Station Limits: This is complete area of station yard under the control of Station Master
and is covered by outermost signals of the station except where otherwise specified by railway
authorities under special instructions. As per General Rule book 2007, clause 1.01(52) issued by
Indian Railways, Station limit is defined as “the portion of railway which is under the control of
a Station Master and is situated between the outermost signals of the station or as may be
13
specified by special instructions”. The Station Master is responsible for all happenings in the
Station Limits. (Fig 4).
BLOCK SECTION
DISTANT
STATION SECTION
HOME
BLOCK SECTION
ADVANCED STARTER
STARTER
ADVANCED STARTER
HOME
STARTER
DISTANT
STATION LIMIT
Fig. 4
Station section, Block section and Station Limit
5
Station Section and Block Section: The entire area of track over which a train
traverses is sectionalized into two main segments viz. (i) Station section and (ii) Block section.
(Fig.5.2.a; 5.2.b; 5.2.c, 5.2.d, 5.2.e, & 5.2.f; for semaphore & MACLS signalling area on single
& double line.)
5.1
Station Section: Station section is that part of Station Limits which is not covered by
Block Section. The area of station section varies with the class of station, situated on a double
line or single line section. Based upon General Rules 1.01(54), Station section means:
5.1.1 That section of the station limits at a class `B’ station provided with two aspect signals,
which is included:
i)
on a double line, between Home signal and the Last Stop signal of the station in either
direction; or
ii)
on a single line:
a) between the Shunting Limit Boards or Advanced Starters (if any), or
b) between the home signals if there are no shunting Limit Boards or Advanced
Starters, or
c) between the outermost facing points, if there are no Home signals or Shunting
Limit Boards or Advanced Starters;
5.1.2 At a class `B’ station, provided with manually operated multiple aspect or modified
lower quadrant signals, which is included:
i)
On double line:
a) Between the outermost facing points and the Last Stop signal of the station on
either direction; or
b) Between the Block Section Limit Board, where provided, and the Last Stop signal
of the station in either direction; or
ii)
On single line: Between the Shunting Limit Board or Advanced starters (if any) or
between the outermost facing points, if there are no Shunting Limit Boards or Advanced
Starters.
14
BLOCK SECTION
STATION SECTION
STARTER
STATION SECTION
ADVANCED STARTER OR
SHUNTING LIMIT BOARD
HOME
OUTER
WARNER
OR
400 mts
400 mts
OR
OUTER
WARNER
HOME
STARTER
ADVANCED STARTER OR
Fig 5.2.a
Block section & station section on `B’ class stations on single line section in two aspect
signalling territory
BLOCK
SECTION
STATION SECTION
STATION SECTION
HOME
STARTER
OUTER
WARNER
ADVANCED
STARTER
HOME
STATION SECTION
ADVANCED
STARTER
OUTER
WARNER
BLOCK
SECTION
STATION 'A'
STARTER
STATION SECTION
STATION 'B'
Fig 5.2.b
Block section & station section on `B’ class station on a double line section in two aspect
signalling territory
5.1.3 The Station Section and Block Section of class À’ & `C’ stations overlap each other
while station section of class `Special’ station is defined based upon the layout of the station.
5.1.4 Here it is very important to understand the difference between Station Section and
Station Limits.
5.2
Block Section: As per General Rules book, clause 1.01(10), Block section is that
portion of running line between two block stations on to which no running train may enter until
Line Clear has been received from the Block station at the other end of the block section.
(Fig.5.2.a; 5.2.b; 5.2.c, 5.2.d, 5.2.e, & 5.2.f; for semaphore & MACLS signalling area on single
& double line.)
The Block Station is the station on either ends of a Block Section.
15
16
HOME
180m
ADVANCED
STR
DISTANT
BLOCK SECTION
BLOCK SECTION
DISTANT
ADVANCED
STR
HOME
180m
STATION SECTION
STATION `B'
OR
HOME
180m
DISTANT
ADVANCED STARTER OR
HOME
180m
ADVANCED STARTER OR
DISTANT
OR
STATION `B'
STARTER
STATION SECTION
Fig 5.2.d
Station section & Block section for Multi Aspect Signals on `B’ class station on single line section
STATION À'
STARTER
BLOCK SECTION
STARTER
STATION SECTION
Fig 5.2.c
Station section & Block section for Multi Aspect Signals on `B’ class station on double line section
STATION À'
STATION SECTION
BSLB
STATION SECTION
STARTER
STATION SECTION
6
Fixed Signal: Signal of fixed location called as fixed signal is the means through which
the status of the track on which the train is to move, is communicated to the driver of the train,
now designated as Loco Pilot, by the Station Master at the station or by a train running in the
Automatic Block Signalling section ahead of other train. As per General Rule book clause
1.02.(21), issued by Indian Railways, the fixed signal is defined as “signal of fixed location
indicating a condition affecting the movement of a train and includes a semaphore arm or disk or
fixed light for use by day and fixed light by night”. This signal can be a semaphore arm or a
colour light, housed on a signal post.
Signals are classified by their:
i)
Structural design,
ii)
Usage, and
iii)
Placement
Signals are also used depending upon geographical terrain, traffic requirement, economical
considerations, traction in the section, and modernization in signalling system.
6.1
Classification of fixed signals based on structural design: These signals, depending
upon their structural design are `Semaphore Lower quadrant, Semaphore Upper quadrant,
Modified Lower quadrant and Colour light signals.
Details of signal posts, arms of semaphore signals and signal units of colour light signals shall
be discussed in ensuing volume of this book.
6.1.1
(i)
Mechanical semaphore signal:
Two aspect lower quadrant signalling system (Fig.6.1.1.a): The word `semaphore'
was used first by a Greek historian: `Sema' stands for sign and `Phor' means to bear. A
semaphore signal consists of a spectacle, as it looks like a human spectacle, and an arm
fixed to it. The Fig 6.1.1.a shows Stop and Warner signals on the same post. The arm
of stop signal is square ended,
painted red with a white strip at the
tail end of the signal arm while the
Warner signal is fish tailed painted
red with a white strip in the same
profile as the fish tail of the arm, at
the tail end of the signal arm. The
spectacle bears coloured glasses,
which are red yellow or green
depending upon the aspect to be
Fig 6.1.1.a
displayed. A lamp with the lens to
Two aspect semaphore signal showing Warner
send a focussed beam of light
below outer on the same post
through the coloured glasses, is
pivoted on a base plate with a pin fixed to a signal post.
17
18
HOME
BLOCK SECTION
WARNER
WARNER
BLOCK SECTION
HOME
STARTER
STATION 'B'
STARTER
STARTER
BLOCK SECTION
HOME
STATION SECTION
WARNER
ADVANCED
STARTER
HOME
STATION SECTION
ADVANCED
STARTER
WARNER
BLOCK SECTION
STARTER
STARTER
STATION 'B'
Fig 5.2.f
Station section & Block section for 2 aspect signals on A class double line section
STARTER
STATION 'A'
Fig 5.2.e
Overlpping station section & Block section for 2 aspect signals on À’ class station on single line section
STARTER
STARTER
STATION 'A'
(ii)
(iii)
Modified lower quadrant signalling system (Fig.6.1.1.b): Looking at the constraint
that a lower quadrant semaphore signal could display only two aspects i.e. arm at
horizontal position showing stop in the day and showing red light also in the night,
which
was
grossly
WARNER
HOME
inadequate with the traffic
DISTANT
moving at faster speed the
BSLB
two aspect semaphore signals
were modified by placing
Warner signal below the
main line home signal on the
same doll on which the home
signal was placed. The home
signal is preceded by a
ADVANCED
STARTER
Distant signal. With this the
STARTER
approaching Loco Pilot did
not have to face first signal
Fig 6.1.1.b
of the station as a stop signal
Modified
lower
quadrant
signalling system
while coming from the block
section. A pre-warning serves the same purpose as multiple aspects signalling system.
Multiple aspect Upper quadrant signalling system (Fig 6.1.1.c): Lower quadrant two
aspect signalling system has limitation of communication, which is slightly improved by
modified lower quadrant signalling system. In the upper quadrant multiple aspect
Signalling system the arm and light arrangement is similar to two aspect semaphore
signals. The ‘ON’ aspect is displayed by horizontal position of arm while caution aspect
is displayed by arm raised to 450 above horizontal & proceed aspect by arm raised to 900
above horizontal. It has an advantage of communication being of multi aspects added by
improved visibility in hilly terrain, while in case of lower quadrant signalling the third
aspect could not be achieved as the signal arm if lowered by another 450 got merged
with the signal post while in upper quadrant this aspect is visible, giving advantage of
one more aspect.
Fig 6.1.1.c
Multi aspect upper quadrant signals showing three aspects
19
6.1.2 Multiple aspect colour light signalling system (Fig 6.1.2): The colour light signals,
simple in structure have all the advantages of communication and visibility both in day and
night. Rightly so, the colour light signalling system operated by central panel has been
scheduled for operation in all new installations or replacements. The signal unit houses signal
lamp, a transformer to convert 110V AC to 12V AC, and a Lamp checking relay, meant to
monitor the status of the lamp. The lamp could be two pole double filament, one filament being
main and other being auxiliary or it could be three pole double filament lamp. In case of two
pole double filament lamp fusing of any of the filament shall be detected by dropping of the
lamp checking relay, which shall be treated by the preceding signal as lamp fused & accordingly
less restrictive aspect, shall be displayed by it. The lamp therefore is required immediate
replacement. In case of three pole double filament lamp the fusing one filament shall result in
switching over to the other filament, while simultaneously giving indication to the Assistant
Station Master that one filament has fused. However in this case the preceding signal shall not
detect this situation as lamp fused continue displaying the aspect as in normal case. The lamp
replacement may be done as early as possible. This arrangement as such is an added advantage
over the two pole lamps. In both cases the signal is not blanked off. The signal unit is provided
with a couplet of stepped lenses, outer one being clear while inner one is coloured red or yellow
or green. The electric signal lamp is placed at the focal point of the lenses couplet such that the
desired colour focussed parallel beam of light is emitted. The unit is available in two, three and
four aspect configurations.
Now with the advent of High power Light Emitting Diodes (LEDs), the cluster of LEDs as
sealed and focussed signals in the form of a unit, is being used, housed in the same signal units
in place of 12 Volt signal lamps and lenses. The LED signal unit is lighted by 110V AC or 110V
DC eliminating use of 110V/12V transformer. With the use of LEDs the frequent signal going
blank due to fusing of incandescent signal lamps has been literally reduced to zero.
Junction type route indicators are used with multiple aspect signals. The signal unit is provided
on an offset bracket mounted on the signal post & route indicator on the top of the signal. This
route indicator is capable of providing six route arms, being fixed with each hexagonal face
while for main or straight line no arm in the route indicator is provided. With this the limit of
arm type route indicator is indication for seven routes only. The arm type unit is in two parts, the
central part is with hexagonal shape each face to accommodate one arm of four lamps. The
central body accommodates one lamp called as pilot lamp and is common to all six arms, all the
five lamps placed in route indicator unit form a row. The unit is provided with clear lens, each
lamp displaying focussed white lunar light. The route indicator is provided on the top of signal
post in such a way that top of the signal unit is just below route indicator. For more than seven
routes, `Theatre’ type route indicators are used which display the number of the line on which
the train is being received, through an array of lamps lighted to form the numbers.
The figure 6.1.2 shows multiple aspect colour light signal and a route indicator with one arm with
a four aspect colour light signal unit.
20
Fig 6.1.2
Multiple aspect Colour Light Signal and route indicator
6.1.3 Visibility of signals: The Loco Pilot of the train is very much dependent of visibility of
the signals. Some time is taken by any human being between seeing or hearing some thing and
reacting to the same. This time between seeing or hearing and reacting to the same, is known as
reaction time. So is the case with the Loco Pilot. This time is taken to be seven seconds. A train
moving at a speed of 100 kilometres per hour shall traverse 194 metres in seven seconds. The
second major factor to decide minimum visibility of the signal is the braking distance, which in
turn depends on the braking power, total mass of the train, gradient and the speed of the train.
Taking into consideration all of these factors the minimum visibility of the signals has been
prescribed to be as follows: [GR & SR (NCR) 3.26/3]
Type of signalling system
Visibility
(A) Two aspect lower quadrant signalling system:
i) Outer signal
With 100 KMPH Section speed, 1200 Metres
With less than 100 KMPH Section speed, 800 Metres
ii) Warner signal on a post by
400 Metres
itself
iii) Home, main line starter and
Each signal should be visible from its previous stop signal
Advanced starter signals
iv) Loop line starter signal
200 Metres
v) Warning Boards: Boards of different design for passenger and goods trains at a distance of
1000 Metres, and 1400 metres are provided in rear of first stop signal for passenger and
goods trains respectively to warn the Loco Pilot of approaching train that he is approaching
first stop signal.(fig 6.1.3)
(B) Multiple Aspect signalling system:
i) Distant signal
400 Metres and if Inner Distant is also provided the
visibility for Inner Distant shall also be 400 metres
ii) All other signals at station
Aspect of each signal shall be visible from its previous
signal in the direction of the train
(C) Where adequate visibility of stop signal cannot be maintained, repeater or Co-acting signal
21
shall be provided or speed restriction shall be imposed if the desired level of visibility is not
available.
(D) If no signal indication is available to the Loco Pilot, he shall control the train considering
that the next signal is red.
(E) Warning Boards: Warning Board on its face, facing the approaching train is provided at a
distance of 1000 metres with zebra design and 1400
metres with a circle in between two horizontal
bands, painted in yellow on black background, in
rear of first stop signal for passenger trains and
goods trains respectively in case of two aspect
signalling territory to warn the Loco Pilot that he
is approaching first stop signal. If no signal
indication is visible from the sighting board, the
Loco Pilot shall control his train assuming that the
stop signal ahead is On. (Fig 6.1.3). [GR & SR
(NCR) 3.26/4]
Fig 6.1.3
Goods & passenger warning boards
6.2
Classification of fixed signal based on
usage: The fixed signal is used as a Stop signal, Warner or Distant signal, Shunt signal, Callingon signal, Gate signal, Repeater signal, Co-acting signal, Goods signal, Automatic Block signal
and a signal with À’ marker.
For the purpose of identification meant for specific use the signals are provided with markers on
the signals posts. These markers are alphabets or symbols clamped with the signal arm or post in
case of semaphore signals and written on circular plate clamped on signal post below the signal
unit in case of colour light signals.
6.2.1 Stop Signal: This signal essentially has a Stop aspect, which is its normal aspect also,
be it a two aspect lower quadrant, Modified Lower Quadrant (MLQ), Multiple Aspect Upper
Quadrant (MAUQ) semaphore signal or a Multiple Aspect Colour Light Signal (MACLS). Other
aspect is ‘Off’ aspect. The Loco Pilot shall not pass this signal when the signal is ‘On’ except
when authorised by the Station Master under a written authority to pass the signal at danger.
6.2.2 Warner or Distant signal: The signal is called Warner signal in case of two aspect
signalling system whether it is a semaphore signalling system or colour light signalling system
and Distant signal in case of Multi Aspect Signalling system. The signal is provided with a `P’
marker, which is the letter `P, painted in black on a white circular disk clamped on the signal
post. The normal aspect of Warner or Distant signal is ‘Caution’ in case of lower quadrant two
aspect signalling system, Upper Quadrant Multiple Aspect Signalling system and Multiple
Aspect Colour Light signalling system. This signal does not have Stop aspect. In case of
Multiple Aspect Colour Light signalling System ‘Attention’ aspect is also given in addition to
caution aspect.
There being no Stop aspect on this signal the Loco Pilot is never required to stop on this signal
except when the signal light is extinguished. On a Warner or Distant signal provided with `P’
marker if the signal light is extinguished during night and also during day time in case of
22
Multiple aspect colour light signal the Loco Pilot shall stop at this signal, the Loco Pilot shall
move with cautious speed prepared to stop at the next signal only after satisfying himself that
the signal is provide with a `P’ marker. In case `P’ marker is not there it shall not be possible for
the Loco Pilot to distinguish between a Stop signal and a Warner or Distant signal (in case the
arm of semaphore signal is also not visible), which in turn can result in passing a signal at
danger or waiting on a Warner / Distant signal for which Station Master shall not be issuing a
written authority to proceed, there by detaining the train unduly. This makes `P’ marker very
important.
6.2.3 Shunt signal: Shunting is a process of attachment, detachment, placement of any
vehicle to or from a train which is attached or not to an engine, with or without the help of an
engine. Shunt signals are meant for signalled shunting in the interlocked station section
performed with a loco motive engine. The shunt signal leads moment from one shunt signal to
the next shunt or stop signal whichever falls first in the route.
In Semaphore signalling system, shunt signals are of two type i.e. (i) miniaturised spectacle
with a miniaturised arm and (ii) of `disk’ type which is a circular disk painted white with a red
horizontal strip on its face. When taken off, in case of miniaturised arm type shunt signal the
arm is painted red. During night time it displays red light when Òn’ and a yellow light when
taken Òff’. In case of disk type it displays the red strip in horizontal position when Òn’ and
inclined to 450 to horizontal. During night time the aspects displayed are red and yellow
respectively. These signals may be mounted on a post by itself or on the same post as that of
running signal depending upon operational requirements. (Fig 6.2.3.a).
Fig 6.2.3.a
Semaphore shunt signals from left to right Disk type in two aspect territory, in multiple
aspect territory and arm type, mounted on post by itself, showing ‘On’ & ‘Off’ aspects
In Colour light signalling system, shunt signal is mounted on a post by itself or on the same
post as that of a running signal based upon operational requirement. When mounted on a post by
itself it displays two lunar white lights placed to form a horizontal line meaning thereby its ‘On’
aspect akin to ‘On’ aspect of a semaphore signal which means dead stop and two lunar white
lights placed to form a line inclined at an angle 450 to horizontal, meaning thereby its ‘Off’-
23
aspect akin to Òff’ aspect of a semaphore
signal which means proceed. One of the lamps
is common in formation of line horizontal and
inclined and is known as pilot lamp. When
mounted on the same post as that of a running
signal it displays no light as Òn’ aspect and
two lunar white lights placed to form a line
inclined at an angle 450 to horizontal meaning
thereby its Òff’ aspect. The signal can not be
used for direct reception or despatch of a train
from or to the Block section or Automatic
Fig 6.2.3.b
Block section. The signal may be mounted on a
Colour light shunt signal mounted on post
post by itself and when it is mounted on the
by itself showing ‘On’ & ‘Off’ aspects
post of a running signal it is mounted on an elbow (an offset bracket) below the running signal.
(Fig 6.2.3.b).
'On' Position
'Off' Position
When a shunt signal is mounted on the same post as that of a running signal, both main or shunt
signal can not be taken ‘Off’ at the same time. Either the main signal shall be taken Òff’ or the
shunt signal at any one time.
6.2.4 Calling-on signal: In bigger yards where reception signal is placed at such a distance
and on a route with high density traffic where loss of time to the train is with serious
consequences resulting in queuing up of following trains, the Calling-on signal is provided on
the same post as that of reception signal below the main signal arm or unit to receive the train
when the main running signal has failed or the train has to be received on an occupied line. The
Calling-on signal and the main signal on the post of which the Calling-on signal has been
provided, can not be taken Òff’ simultaneously. The Calling on signal may also be provided on
the post of signals other than reception signals, under special approved instructions except on the
post of last stop signal.
i)
Calling-on Signal in Semaphore Signalling system, [GR 3.13] be it lower quadrant or
upper quadrant it has miniaturised spectacle fitted with a miniaturised arm painted white
in colour with a red strip near the end
of the arm. The signal displays arm in
horizontal position to show ‘On’ aspect
during day time. In case of lower
quadrant signalling system the arm is
inclined to 450 below horizontal and in
case of upper quadrant system the arm
is inclines to 450 above horizontal to
display ‘Off’ aspect during day time
Fig 6.2.4.a
and also shows yellow light during
Miniature arm lower quadrant calling on
night time. (Fig 6.2.4.a & b).
signal fixed below main stop signal
24
C
Fig 6.2.4.b
Miniature arm upper quadrant calling on
signal fixed below main stop signal
ii)
C
Fig 6.2.4 c
Miniature colour light calling on signal fixed
below main stop signal
In Colour light signalling system it is miniaturised unit provided on the same post as
that of the corresponding main signal on an elbow (Offset bracket), below the running
signal unit. It displays no light in Òn’ aspect and miniaturised yellow light as Òff’
aspect during day as well as night time. (Fig 6.2.4.c).
It must be ensured that the train approaching the concerned reception signal has come to
a stop before the Calling-on signal acquires Òff’ aspect.
6.2.5 Gate signal (Fig 6.2.5): Level crossing gate falling in the Block section, when
interlocked, is provided with the Gate signals on either side of the gate to protect the road traffic
across the gate. It is provided at a distance of 180 metres in case of multiple aspects signalling
system and at a distance of 400 metres in case of two aspect signalling system, from the edge of
the road on either side. The signal is preceded by a Warner or Distant signal depending upon the
system of signalling of the section. A gate signal is essentially same in structure and design as an
stop signal in semaphore signalling system as well as in Colour light signalling system provided
with a ‘G’ marker on its post in addition.
The ‘G’ marker is letter ‘G’ painted in black on a circular disk painted yellow. The disk is
clamped with the signal post. The gateman posted on duty at the level crossing gate is not
competent to issue authority to pass the gate signal on red. The provision of the `G’ marker on
the signal distinguishes the signal for following rules of the gate signal.
(i)
On a gate signal in Block Section, the Loco Pilot shall stop at the signal & whistle in
prescribed code, wait for one minute during day and for two minutes during night and if
the signal is not taken ‘Off’ during this time the Loco Pilot shall move his train ahead
cautiously up to level crossing and if the gate man is available and exhibiting all right
signal he shall pass the gate cautiously but in case the gateman is not available or is
available but not exhibiting alright signal, it shall be ensured that the gate is closed and
25
(ii)
(iii)
then pass the gate cautiously following the hand signal by the gate man or in his absence
by one of the engine crew members of the train.
The gate signal provided in the Automatic Block Signalling section is provided with ‘A’
marker and a ‘G’ marker. The ‘A’ marker is the letter ‘A’ stencil cut on black painted
glass sheet on the face of ‘A’ marker
signal unit or, which is provided on
an offset bracket on the same signal
post to which is qualifies. In case of
LED signals where used the letter
À’ is displayed in the face of the
LED signal unit. The ‘G’ marker is
the letter ‘G’ painted in black on a
A
circular disk painted yellow and
G
clamped on the signal post. The ‘A’
marker is lighted to show that the
Gate is closed and locked against
fig 6.2.5
road traffic. When the ‘A’ marker is
LED
À’
marker,
fixed on gate signal in
not lit the signal is treated as manual
Automatic
Block
section
area with a `G’ marker
signal and provisions of Gate signal
provided on an interlocked gate in Block section in Absolute block signalling section
shall be followed as described above in paragraph (i) above. See fig.6.2.5
The gate provided in the station sections are protected by main running signals of the
station and are accordingly interlocked to these signals.
6.2.6 ‘A’ Marker on signals in station section: The signals provided with À’ marker in the
station section wherein adjoining section is worked as Automatic Block signalling section when
lit means that the signal is working as automatic signal and when the À’ marker is not lit it
means that the signal is working as manual stop signal and the Loco Pilot shall follow rules of
manually operated signals.
6.2.7 Repeater signal: In cases when a signal is not visible to the Loco Pilot from adequate
distance due to curvature or any other reasons or in cases where signal is not visible to the guard
of the train at the rear end of a platform, a repeater signal is provided at a suitable convenient
position in rear of main signal.
A repeater signal is provided with an 'R' marker and is of the following type.
(i)
(ii)
(iii)
A square ended semaphore arm painted yellow with a black band near the tail end of the
arm.
A Colour light repeating signal.
A rotary or disc banner type signal.
These three types of repeating signals in their Òff' position are shown in fig.6.2.7. It is pertinent
to note that a repeater signal essentially does not have a red aspect. The post of semaphore
repeater signal is provided with a white circular disk painted with letter `R’ in black while the
post of colour light signal is provided with a black circular disk panted with letter `R’ in white.
26
R
R
The ‘On’ aspect in case of
semaphore repeater signal
during day is a horizontal arm
painted yellow with a black
band at the square end of the
arm, and during night it
displays yellow colour light.
This signal displays green
light during night time when
taken Òff’, its arm inclined
to 450 below horizontal.
R
Fig 6.2.7.
Off aspects of repeater signals semaphore , banner type and
colour light from left to right
The Banner type repeater
signal disk is painted with
black strip across its diameter
with a yellow strip in the middle of it, which is horizontal when the signal is Òn’ and inclined
to 450 when Òff’ The colour light repeater signal displays green colour to repeat the Òff’
aspect of the main signal and yellow colour when Òn’.
6.2.8 Co-acting signal (fig.6.2.8): The signal to
which the train is approaching should be
continuously visible to the Loco Pilot. Whenever a
signal is not visible to the Loco Pilot continuously
obstructed by over bridge, flyover, or any other
structure, another signal is placed on the same post,
as that of main signal, at a suitable height to enable
continuous visibility of the signal to the Loco Pilot.
This signal known as co-acting signal is an exact
replica and moves in unison together with its main
signal semaphore signal as well as colour light signal.
Fig.6.2.8
Off aspect of Co-acting signals
6.2.9 Goods signal (fig 6.2.9): A semaphore reception signal provided with stencil cut letter ‘O’
on the signal arm encircling the
white strip of red painted arm
provided on a post by itself or on a
doll along with other running
signals leads the train to goods
running lines only.
6.2.10 Dock signal (fig 6.2.10):
A semaphore reception signal
provided with stencil cut letter ‘D’
on the signal arm encircling the
white strip of red painted arm
provided on a post by itself or on a
fig 6.2.10
On aspect of Dock signal
27
fig 6.2.9
On aspect of Goods signal
doll along with other running signals leads the train to dock platform.
6.2.11 Signals at class `D’ station: At a `D’ class station, a train may be stopped under manner
authorised by special instructions. To indicate to the Loco Pilot that he was approaching a `D’
class station an indicator board shall be provided by the Engineering department with letter `H’
of 300 mm height, painted black on a sheet. Painted yellow at a distance of 600 metres from the
centre line of the station. The board shall be 600mm X 600mm.on a 2 Metres post painted white
and black alternate strips of 300 mm height each.
6.2.12 Automatic Block signal: The Automatic Block signals are either three aspect or four
aspect Colour Light signals. In three aspect signalling scheme each signal has essentially Red,
Yellow and green aspects It shall have double yellow aspect also if the signal is a in four aspect
signalling scheme. The normal aspect of this signal is always green. The aspects of these signals
are controlled by passage of the train. As soon as a train passes over the track circuit ahead of
the Automatic Block signal, the aspect of the signal becomes red. As the train moves on and not
only clears the next signal but also signal over lap beyond the same, the aspect of the signals
turns to yellow and this keeps on changing to double yellow and green as the train moves ahead
of next to next signal along with overlap and then next to next to next along with overlap. The
following train shall be guided by the aspects as being displayed to it as per extent rules. The
aspect sequence, with reference to train movement may be seen in fig. 6.2.12.a in three aspect
signalling areas and 6.2.12.b in four aspect signalling section.
fig.6.2.12.a
Aspect sequence of three aspect Automatic Block signal
28
TRAIN
TRAIN
TRAIN
TRAIN
TRAIN
fig.6.2.12.b
Aspect sequence of four aspect Automatic Block signal
6.2.13 The ‘Position’, ‘Aspect’ and ‘Indication’ of signals: The signal is only means of
communication between the persons at the ground and the Loco Pilot or any other person on the
Loco. For communication, there is always a language. The language used for this
communication is a combination of `Position’ Àspect’ and Ìndication’ of the signal as
discussed below:
i)
Position of the signal: Any signal shall have two `Positions’ which is Òn’ or Òff’.
The arm of a semaphore signal shall be painted with the same colour as the light it
displays during night in its horizontal position, this position of Semaphore signal is
called Òn position’ The arm is painted red in case of sop signal and yellow in case of a
Warner signal. Both signals, when their arm is horizontal, shall be said to be in their Òn
position’. Since the colour light signal displays same light during day as it displays
during night, it is called to be in Òn position’ when it is normal, it may be a Stop signal
or a Distant signal. Any other position of the arm of semaphore or colour light signal is
called ‘Off position’ except in case of a signal in Automatic Block signalling territory.
In Automatic Block Signalling area only colour light signals are to be provided. The
signals remain in Òff’ position normally.
ii)
Aspects of the signal: A Stop signals, in its ‘On position’ conveys ‘Stop Aspect’ while
a Warner or Distant signal in its ‘On position’ conveys ‘Caution aspect’.
A two aspect semaphore stop signal in its Òff position’, arm inclined to 450 below
horizontal and a green light by night, conveys `Proceed Aspect’ while; A Multiple
Aspect Upper Quadrant semaphore signal inclined to 450 above horizontal with a yellow
light by night or a Colour Light Signal displaying yellow colour light, in its Òff
position’ conveys `Caution Aspect’.
29
A Multiple Aspect Upper Quadrant semaphore signal raised to 900 above horizontal
with green light by night or a colour light signal displaying green colour light, in its Òff
position’ conveys `Proceed Aspect’.
A Multiple Aspect Colour Light Signal displaying double yellow colour lights, in its
Òff position’ conveys Àttention Aspect’.
iii)
Indication conveyed by the Aspect of the signal: The detailed meaning of the Aspect
of signals is of the certain meaning to the Loco Pilot or any observer.
a) Stop aspect indicates stop dead;
b) Proceed aspect indicates proceed. Here Proceed means proceed with the maximum
permissible speed in the area;
c) Caution aspect indicates proceed and be prepared to stop at next stop signal;
d) Attention aspect indicates proceed and be prepared to pass next signal at such
restricted speed as may be prescribed by special instructions. In this situation if the
train is indicated to move on straight line, the next signal shall be passed on Caution
aspect prepared to stop at next signal with Stop aspect, but if the train is indicated to
traverse a 1 in 8 ½ turnout, the Loco Pilot shall have to restrict the speed at 15
kilometres per hour or if the turnout happens to be I in 12, the speed shall be
restricted to 15 kilometre per hour and so on. The speed on 1 in 12 turnouts has been
increased on certain sections to 30 KMPH.
The Aspects and corresponding indications are tabulated below in Table 6.2.13:
Position
Aspect
Indication
Two aspect Semaphore stop signal:
‘On’
Stop
‘Off’
Proceed
Outer & Warner on the same post:
Outer ‘On’ & Warner ‘On’
Stop
Outer ‘Off’ & Warner ‘On’
Proceed
Outer ‘Off’ & Warner ‘Off’
Proceed
Multiple Aspect Signal:
‘On’
Stop
‘Off ’
Caution
Stop Dead
Proceed
Stop dead
Proceed with caution
Proceed
Stop Dead
Proceed & be prepared to stop at next
signal.
‘Off ’
Attention
Proceed & be prepared to pass the next
signal at such restricted speed as may be
prescribed bys special instructions
‘Off ’
Proceed
Proceed
Modified Lower quadrant: Main line Home and Warner on the same doll:
Home ‘On’ & Warner ‘On’
Stop
Stop dead
Home ‘Off’ & Warner ‘On’
caution
Proceed & be prepared to stop at next signal
Home ‘Off’ & Warner ‘Off’
Proceed
Proceed
Shunt signal semaphore & colour light:
30
‘On’
‘Off’
Calling on signals:
‘On’
Stop
Proceed slow
Stop dead
Proceed with caution for shunting
- -
Loco Pilot should follow the aspect of main
signal.
‘Off’
Proceed slow Stop and then draw ahead with caution and
be prepared to stop short of any obstruction
Automatic Block Signal on single or double line:
‘On’
Stop
Stop for one minute in the day and two
minutes during night and then follow the
procedure described in Chapter-III &
paragraph 3.8 & 3.2 respectively, of this
book.
‘Off’
Proceed
Proceed
‘A’ marker on semi-automatic Stop signal:
White illuminated letter ‘A’
- The stop signal is working as Automatic
against black background.
signal. Follow rules of Automatic signal.
Letter ‘A’ extinguished
- The stop signal is working as Manual stop
signal. Follow rules of stop signal.
Same as home signal provided at
Intermediate Block stop signal:
intermediate block post
Same as main
Co acting signals:
signal
- Repeating signals:
‘On’
- Signal to which it repeats is ‘On’, proceed
to stop at the signal to which it repeats.
‘Off’
- Signal which it repeats is ‘Off’, proceed to
the signal to which it repeats and act
according to the aspect after reaching there.
Goods signal:
‘On’
Stop
Stop dead
‘Off’
Proceed
Proceed, signal is for goods running line
only
Dock signal:
Stop
Stop dead
Proceed
Proceed, for Dock Platform only
Here proceed means proceed at maximum permissible speed permitted for the section.
Table 6.2.13
The aspects, indications and their meaning
6.3
Classification of signals based on placement: On a station, a fixed signal can be
placed as reception or a departure signal.
31
6.3.1 Reception signals: In two aspect semaphore signalling system reception signals are
Outer, Warner and Home. In Multiple aspect signalling system reception signals are Distant and
Home.
(i)
Warner /Distant signal: In two aspect signalling area the first signal faced by the Loco
Pilot is Warner. This signal is placed on a post by itself or two metres below the Outer
signal on the same post as Outer. The arm of the signal is fish tailed with its face painted
red with a white band parallel to the fish tail, (fig.5.2.a & 5.2.e).
When placed on a post by itself a fixed green light is provided 1.5 to 2 meters above the
arm. The signal shows by night, a red light when in Òn’ position and a green light when
in Òff’ position along with the fixed green light above it. The fixed green light is
replaced by the Outer signal when the Warner is placed on the same post as Outer
signal.
Two aspect colour light Warner signal also displays same aspects by day and night
both as semaphore signals display by night in both situations as when placed on a post
by itself or on the same post as outer signal.
Distant signal in Modified, two aspect semaphore signalling territory: The arm of
the distant signal is fish tailed, its face painted yellow with a black band parallel to the
fish tail. The signal shows yellow colour light by night when Òn’ and one green when
taken Òff’.
The Distant signal in Upper Quadrant arrangement is such that a hole provided in the
disk moving with the arm obstructs the yellow light of the lamp placed 1.5 metres below
the arm, such that the view of the fixed lamp is obstructed in other two positions of the
arm of the signal except when it is inclined to 450 to the horizontal.
Distant signal in Semaphore Multiple Aspect Upper Quadrant (MAUQ) signalling
territory has fish tailed arm with its face painted yellow with a black band painted
parallel to the fish tail. This shows yellow light by night when Òn’, one yellow light
with another yellow light when inclined to 450 above horizontal and green light when
Òff’ at 900 above horizontal.
(ii)
Distant signal in Multiple Aspect Colour Light signalling territory, also displays the
same colours as MAUQ signals by day as well as by night. In sections with Rajdhani
trains route or where heavy Haul goods trains are run, two distant signals are provided
preceding Home signal. The first Distance signal encountered by the Loco Pilot is called
distant signal. Its signal post is painted with black and yellow strips of 12” each. The
next distant signal post is painted with aluminium paint. Both the signals are provided
with a `P’ marker plate on their post and other wise are identical.
Outer signal: An Outer signal is first stop and reception signal in two aspect lower
quadrant signalling section only. The placement of Outer signal varies depending upon
the section being single line or double line. In case of two aspect signalling the adequate
distance beyond the first stop signal of the station is 400 metres as such in case of
double line section the outer is placed at a distance of 400 metres from the next
32
(iii)
reception signal i.e. Home signal. If the section is single line, the outer signal has to be
place at a distance of 400 metres from the last stop signal which is Advanced starter
signal. The advanced starter signal is placed at a distance of 120 metres from the last
trailing point in single line section. The block section extends not only upto first stop
signal but also an adequate distance beyond the first stop signal which is 400 metres in
this case as such with the entry of the train inside outer signal and clearing the adequate
distance of 400 metres the train enters into Station Section having cleared the Block
section.
Home signal, Routing Home signal & Route indicators: After the outer signal, the
next reception signal towards the station is Home signal. The purpose of this signal is to
inform Loco Pilot of the line to which the train is being received. In two aspect lower
quadrant or colour light signalling section Home signal is provided right at the
entrance, short of points meant for diversion of the train to the nominated line because
the block overlap is provided just beyond outer signal. There are different signals on
small posts called `Dolls’ mounted on a `gantry’ provided on single signal post, for
different lines in case there are more than on lines for the train to be received. The doll
bearing main line signal is kept higher than all other dolls on the same gantry while the
signals have to be placed in sequence such that the outermost signal pertains to the
outermost line and the inner most to innermost line. This arrangement works as route
indicator to the Loco Pilot (Fig. 6.3.1.a).
In some cases when under approved special
instructions two or more signals are to be
provided on the same post, the top most
signal shall apply to the extreme left line,
next signal to next line and so on so forth.
Under exceptional circumstances two home
signals are to be provided on the same post
the main line signal shall be placed higher
then the other signal.
In Multiple Aspect Colour Light signalling
section, the Home signal post and unit is one
for all reception lines. When there are more
than one reception lines, route indicator is
Fig.6.3.1 a
provided on the top of the signal post which
Semaphore Home and routing home
indicates the route on which train is intended
signals on a gantry
to be received. When Junction Type i.e. five
lamps lit in a row formation, route indicator is used, the maximum routes that can be
covered by one such route indicator are seven. In such a situation another Home signal
is provided just before second set of reception lines. When it is not considered to
provided another intermediate signal for another bunch of routes, theatre type route
indicator is used which displays routes in numerals formed by array of lamps, when the
number of routes to be indicated by the signal is more than 7. However theatre type of
route indicator shall be used to display maximum number of ten routes.
33
One of the purposes of indicating line to the Loco Pilot, on which the signal is leading to
is, to enable Loco Pilot observe speed restriction of 15 Kmph and 30 Kmph while
negotiating 1 in 8 ½ and 1 in 12 turnouts respectively, while entering into a loop line.
Where the reception lines are situated scattered in the form of bunches, the branching
off is required to be done at different stages requiring inturn more number of signals in
between the first reception signal and the last berthing track of the yard. In such a
situation intermediate home signals are provided. (Fig. 6.3.1.b)
DISTANT
HOME
ROUTING HOME
Fig.6.3.1.b
Colour light Home and routing home signals
6.3.2 Departure signals: Starter and Advanced starter signals are departure signals. A signal
at a block station which is controlled by the block instrument and after passage of this signal the
train enters into the block section is also known as Last Stop signal (LSS).
(i)
(ii)
Starter signal: This is the first signal permitting despatch of a train from the station.
The signal is provided at the departure end of each line. In case there is no Advanced
Starter at the station this signal is interlocked with the block instrument and permits
entry of the train into the block section only when the line clear has been obtained from
the station in advance. The starter signal is provided with a route indicator if more than
one line is taking ‘Off’ from the station. However when Advanced starter is provided at
the station the starter signal permits movement of the train up to advanced starter signal
only and is not interlocked with the Block instrument. The starter signal is not used for
shunting.
Advanced Starter signal: This signal is the last stop signal of the station and is
interlocked with the Block instrument in such a way that it is not possible to take this
signal ‘Off’ unless line clear has been obtained from the station in advance.
An independent Advanced starter signal is provided for each main or branch line taking
‘Off’ from the station provided after all points at the station. (Fig. 6.3.2)
34
ADVAN
CED ST
ARTER
ADVANCED STARTER
Fig. 6.3.2
Independent Advanced starter signal for each departure line out side all points of the station
7.
Interlocking in the station section: In a complex network where the traffic is heavy, it
is important that the signal is taken ‘Off’ only after ensuring that the track is clear, points are set
and secured for the scheduled route on which train is to traverse, interlocked level crossing gates
falling in the route of train including overlap are closed and locked for road traffic. This
eventually means that a desired sequence of operation of points and signals is required to be
ensured before the signal can be taken ‘Off’. This desired sequence of operation is achieved
through interlocking of these equipment with each other through mechanical, electrical or
electronics means. As per General Rule book 2007, clause 30, chapter- I, issued by Indian
Railways , the interlocking is defined as “an arrangement of signals, points and other appliances
, operated from a panel or lever frame, so interconnected by mechanical locking or electrical
locking or both that their operation must take place in proper sequence to ensure safety”. The
interlocking is defined in Railway Signalling published by B.S.I as number 719/1936 as “an
electrical or mechanical means of making the operation of one piece of apparatus is dependent
upon the operation of certain predetermined conditions being fulfilled by other apparatus”. With
the advent of Solid State interlocking this stands modified to add ‘electronic’ to èlectrical or
mechanical’ in the above definition. The interlocking can therefore be understood as ‘an
arrangement through which operation of points and signals in a pre determined sequence is
ensured’.
7.1
The basic rules to be observed while designing interlocking which is predetermining
sequence of operation of points, locks, closing of level crossings etc., have been given as
essentials of interlocking in signal Engineering Manual 1988 part-I paragraph 7.82, as
reproduced in following paragraph:
7.1.1 Essentials of interlocking: Lever frames and other apparatus provided for the operation
and control of signals, points, etc., shall be so arranged as to comply with the following
essentials (SEM part-1, 1988 clause 7.82) :
i)
ii)
It shall not be possible to take “ OFF’ a running signal, unless all points including
isolation are correctly set, all facing points are locked and all interlocked level
crossings closed and locked against public road for the line on which the train will
travel, including the overlap.
After the signal has been taken ‘OFF’ it shall not be possible to move any points or lock
on the route, including overlap and isolation, nor to release any interlocked gates until
35
the signal is replaced to the ‘ON’ position.
iii)
iv)
It shall not be possible to take ‘OFF’ at the same time, any two fixed signals
which can lead to any conflicting movements.
Where feasible, points shall be so interlocked as to avoid any conflicting
movement.”
It is very important to understand that it is the signal, which is taken ‘Off’ last, after ensuring
essentials of interlocking, be it operated by a lever or taken ‘Off’ electrically/electronically, only
when all points en-route have been set for the route on which train is intended to move, this
should include overlap, all points falling in facing direction of the train are locked including
points falling in overlap as if the train was to pass over these points as well, all level crossing
gates which are interlocked with the signals and fall not only within the route but also in the
overlap, have been closed to road traffic and locked, while at the same time no two signals
should come ‘OFF’ simultaneously which may conflict route of the train. The signal being the
last, it should always be possible to put it back to ‘On’ in case of emergency, without any
hindrance, by lever in lever frame or by push button on panel.
7.2
Correspondence between operating and operated units:
7.2.1 All signals, points, Locks on points, Level crossing gates, inter-cabin slots, Block
working system and any other equipment involved with the train movement are operated by
levers in case of mechanical system, switches or buttons if it is electro mechanical or electrical
system and buttons or a visual display unit (VDU) with a key board similar to computer system,
if it is electronic system of operation and interlocking. These devices may be called operating
devices.
7.2.2 On station interlocked to standard – III and above, the operating units are required to be
grouped together in one place and interlocked. These operating devises transfer command to
operate the signals, points, Locks on points, Level crossing gates, inter-cabin slots, Block
working system and any other equipment involved with the train movement. These equipment
may be called as operated units. A medium to carry command to these operated units is wire run
for signals and rod, in case of points in mechanical system and a cable in case of electrical or
electronic system of operation and interlocking.
7.2.3 Although all measures are taken to ensure that there is no failure of correspondence
between a command given through operating unit and the operation of the equipment but in case
of such a failure the outcome could be disastrous, as interlocking shall permit taking ‘Off’ of the
concerned signal while at site the conditions shall not be conducive for passage of train. As such
a process of correspondence check is inculcated in the system without which any amount of
interlocking shall be of no avail. The devices for checking correspondence are Circuit Breakers
(CB) attached to signal arms to check that the signal is ‘Off’ or ‘On’ in correspondence with the
signal lever, a point detector is used to check if the point is set to normal or reverse and the lock
plunger on the point has moved its full travel in correspondence to the lever operating it, in
mechanical arrangement. In electrically operated equipment the signal aspect is checked for
signal being lighted ‘On’ or ‘Off’ through lamp checking devices/relays similarly the setting of
point operated by electric point machines to be normal or reverse and locked properly, is
36
checked by electric detector inbuilt in the point machines, or in older version, associated with
point machines.
The method of achieving the system of correspondence check is dealt with in ensuing volumesIII & IV of the book.
7.3
Other ingredients of interlocking:
7.3.1 Route holding: In terms of second essentials of interlocking, as mentioned in preceding
paragraph, after the signal has been taken ‘Off’ it shall not be possible to move any point or lock
on the route, including overlap and isolation until the signal is replaced to the ‘On’ position.
Route as mentioned here covers all points, locks and Level crossing gates on track, in between
signal and the destination as well as the overlap that is the specified distance of 180 metres in
case of two aspect signalling and 120 metres in case of multi aspect signalling, beyond the signal
next to the signal for which route holding is considered here.
This can be achieved either mechanically or electrically or a combination of both.
When a train is approaching the station from a Block section and the Loco Pilot sees the signal
approaching as ‘Off’, the route to which the signal leads should get locked and it shall not be
possible to be disturbed. It is possible only when there is a track circuit available between the
Sighting Board and the signal which when occupied shall detect arrival of the train within
normal baking distance.
It shall also not be possible to disturb the route even when the train has passed the signal and
even it is replaced to ‘On’, till the train has reached its destination.
7.3.2 Approach Locking: Holding the route beyond the signal, to which it leads, while the
train is approaching, is called ‘Approach Locking’. When the train is approaching a signal and
the Loco Pilot has seen the signal ‘Off’, which means accepted the signal as ‘Off’, he shall get
busy in taking action with reference to the aspect of signal. In case the aspect was green he shall
further get relaxed and continue to move at optimum speed, but if the signal is ‘Off’ with
Caution or attention aspect the Loco Pilot shall be further busy in controlling the speed of the
train depending upon the aspect of the signal. By the time he gets relaxed he must have traversed
considerable distance. During the intervening period at a speed of 60 KMPH he shall have
traversed one KM in one minute which means if the Distant signal is at one KM from home he
shall be almost crossing the home signal. Putting back the signal lever in order to change the
route at the last moment when the Loco Pilot has accepted the ‘Off’ aspect, shall be extremely
dangerous if the train encounters an unlocked or moving point under the wheels. The approach
locking can be provided only when the track between the signal, being approached, and the
sighting board, when the train is approaching the station from block section, is track circuited.
Generally this is available only when Automatic Block signalling is provided in the adjoining
block section where track circuits are available by default. However at stations provided with
panel interlocking, entire yard is track circuited as such approach locking for all other signals in
the yard is available except for Home signal and for Shunt signals provided on siding which are
not track circuited to entire length of the siding.
37
When a track circuit has been provided between the Sighting Board and the signal to which the
Loco Pilot is approaching from the Block section, the route gets approach locked as soon as the
track circuit is occupied by the approaching train. The route shall not be Approach locked till the
train occupies the track circuit and in such situation it shall be possible to change the route. In
such a situation the route shall be released immediately upon putting back the signal. After the
Loco Pilot has accepted the signal, the route shall be released when the train reaches its
destination, in normal course. See figure 7.3.3 in which the route has been shown as set for
reception of train on loop line with destination as its berthing portion between the two opposite
signals on the same line.
7.3.3 Dead Approach Locking: Approach locking is known as ‘Dead Approach locking’
when the signal, once taken ‘Off’, locks the route dead and the route can not be released upon
putting the signal back to ‘On’ except after a lapse of 120 seconds after the signal is put back to
‘On’, since there is no means to hold the route such as a track circuit at a place where the Loco
Pilot accepts the signal. As discussed in preceding paragraph, the Dead Approach Locking is
required to be provided for routes of signals leading from non track circuited approach track,
which usually are Home signals and Shunt signals.
DESTINATION
SIGHTING
BOARD
DISTANT
Overlap
120mts.
ROUTE
HOME
TRAIN
STARTER
ADVANCED STARTER
7.3.4
(A)
(B)
STARTER
fig. 7.3.3
(Dead) Approach Locking
Ways and means to achieve Approach locking and Dead approach locking:
Through Mechanical means: The Approach or Dead Approach locking is achieved
manually, in case of operation of points & locks by levers in the lever frame, by keeping
the lever of the Stop signal to which the Loco Pilot is approaching, in pulled position.
The entire route ahead of the signal i.e. facing point locks, points and level crossing
gates, falling in the route of signal remains locked by the signal lever in the interlocking
frame, only up till the signal lever is kept in pulled position. As soon as the signal lever
is put back to normal the entire interlocking ahead of signal gets free, but is kept locked
by Back locking.
Through track circuits: The Approach locking is achieved by providing the track
circuit between the sighting board and the concerned signal when the train is
approaching from the Block section and for other signals which are preceded by track
circuits in the yard. The maintenance of such a track circuit out side station section, is
quite difficult and is more prone to interference from outsiders, as such is not very much
used. However when the adjoining Block section is provided with Automatic Block
signalling, the track circuit is available between the Home signal of the station and
38
preceding Auto Block signal and as such is used for the purpose of Approach locking
also. The route is kept held through selection circuits. However the route can be released
even after the Loco Pilot has accepted the signal, by putting back the signal and
ensuring that the train has come to a stop, after 120 second of action taken to release the
route.
7.3.5 Back Locking: After the train has passed the signal, it is important to put back the
signal to ‘On’ which in turn shall release entire route ahead, which was kept locked by the signal
lever or approach locking circuits so far. When a track circuit is provided ahead of the signal, the
signal is replaced back by occupation of the track circuit. In case of mechanical signal the
reverser provided with the signal is released putting back the signal to Òn’ and in case of colour
light signal the signal is put back to ‘On’ by occupation of track circuit through selection
circuits. Occupation of this track circuit also simultaneously initiates back locking circuits.
(A)
Back locking Mechanically: All facing points, trailing points and facing point locks
enroute get locked by the signal lever in interlocking trough provided with the lever
frame and are kept locked till the signal lever is put back to normal. In cases where the
signal is put back to Òn’ by occupation of signal replacement track circuit, by the train,
provided just ahead of the signal, the operator is at liberty to put back the signal lever,
unlock the point and operate it while the train is still traversing the route, be it reverser
controlled semaphore signal or multiple aspect colour light signal. As such under such a
situation (i) the signal should be placed as close to the corresponding first facing point
as possible, (ii) In case the signal is more than 180 metres from the corresponding facing
point, a holding bar shall be provided in such a way that the distance between the signal
and holding bar and between point and holding bar does not exceed 180 metres. It must
further be ensured that the if next facing point lock bars on the route of the train are not
within 180 metres from the centre of the immediately preceding lock bars, a holding bar
is inserted in between the two such points such that the distance of the holding bar is not
more than 180 metres from the adjoining facing point lock bar on either side under any
circumstances. These lock bars and holding bars are interlocked in such a way that first
lock bar or holding bar which ever the train shall encounter first after passing the signal
shall keep all the lock bars and holding bars in the route of train held till the last lock bar
is released by train thereby holding all points enroute.
At stations where trains are allowed to run through at an speed of more than 50 KMPH,
the trailing points should also be held by providing fouling bars along with chain of
holding bars if the distance between such a trailing point and signal controlling the same
is more than 180 Metres, as described above, such that the distance between successive
holding bars does never exceed 180 metres.
The provision of Lock bar, holding bar or fouling bar can be substituted by track circuits
as the situation may warrant which some times occurs due to non-availability of
adequate space to accommodate a full length lock/ holding bar, between points.
(B)
Back Locking by Electrical Means: (Fig 7.3.5) In the same analogy as mechanical
interlocking where levers controlling points and lock bars are held by signal lever
through interlocking in the lever frame and by lock bars and holding bars at site, ‘Back
39
Locking’ is achieved through selection circuits electrically. It is easy as well as more
effective to hold the route by track circuiting in the entire yard, as the points in the route
DESTINATION
SIGHTING
BOARD
DISTANT
HOME
Overlap
120mts.
ROUTE
TRAIN
STARTER
ADVANCED STARTER
STARTER
fig. 7.3.5
Back Locking
ahead of train, are kept locked continuously till the train keeps the track circuits
occupied. Providing the entire yard with track circuits is not always economically viable
unless the station is provided with panel/ relay interlocking, where track circuiting the
entire yard it is an essential requirement.
Method of achieving route holding electrically shall be discussed in details while
dealing with selection circuits in ensuing volume IV of the book.
7.3.6 Track Locking: It is holding the points locked while it is under the wheels of a train.
Mechanically it is done by attaching a lock bar to the facing point lock. The length of the lock
bar is kept as such to cover the maximum distance between the two successive wheel bases of
any vehicle. The length of lock bar is accordingly kept to be 42 feet. The lock bar attached with
the facing point lock plunger moves to-and-fro along with the plunger through a radial guide,
due to which the lock bar has to lift upto rail top level. The unlocking movement of the plunger
is not possible if a wheel is over the lock bar as the flange of the wheel shall not allow the lock
bar to be lifted to the level of rail top.
Electrically, the track locking is also provided through track circuits in the entire point zone. The
occupation of the track circuit detects presence of a train over the point zone, which keeps the
point locked through selection circuits.
7.3.7 Check Locking and Indication Locking: When points are operated by lever in cabin
and electric point machine at site, a lever lock is provided on the point operating lever for the
purpose of track locking. The lever can be moved if i) it is not locked in the lever frame,
interlocked by any other lever, ii) if it is free, it shall be possible to move the lever to the extent,
upto which it does not actuate point operating circuit which is point beyond which it shall not
move if the point zone track is occupied and the lever lock, locks the further movement of the
lever, iii) the lever shall move further if lever lock is free, it shall then initiate point operating
circuit from normal to reverse if the lever is moving normal to reverse or vice-versa, iv) it shall
not be possible to set the lever to final normal or reverse position unless the point has physically
moved to the position corresponding to the lever position in the lever frame.
Holding the lever in its initial stage when the point is track locked is ‘check Locking’ and
holding the lever while the point is being set, till it is set is ‘Indication Locking’. This is another
40
example of checking correspondence between operating and operated equipment.
7.3.8 Sectional route release: In yards where more than one cabins have to be provided,
the train movement takes place with close coordination between cabins associated with the given
train movement. This coordination is implemented through inter-cabin slotting.
In railway signalling language a ‘Slot’ is the permission given by any of the agency controlling
train movement to another agency distantly placed associated with the other one. If there are two
cabins one cabin has to ascertain fulfilment of all conditions for the movement of the train in the
area under his control and the other cabin has to do the same for his area. The movement of the
train can take place only when the entire relevant area of the station fulfils all conditions. To
ensure this the leading cabin has to communicate to the other cabin, through electrical or
mechanical means about fulfilment of all conditions. This communication is giving `Slot’. In
this case as soon the train passes through the cabin at the receiving end, another train movement
not affecting the area of the other cabin such as shunting, or departure of train etc can be done,
thereby saving time.
On bigger stations where more than two cabins are required the inter cabin slotting at one hand
delays the train movement while at the other hand is useful in releasing the area of one cabin as
soon as the train clears the area of the cabin concerned, thereby allowing other movements to
take place thereby saving time. This release of route of the area of the cabin freeing it for use for
another movement is ‘Sectional Route Release’. This arrangement is better utilised in bigger
yards provided with Central panel, end cabin panel and Route Relay Interlocking.
This concept of sectional rout release is used best in case of Centrally Operated Panel or Route
Relay Interlocked stations eliminating totally the disadvantages of loss of time due to multi
cabin Slotting.
7.3.9 Locking of last trailing point by the Last Stop Signal: In situation when a small train
such as a light engine or tower wagon stops at the foot of Last Stop Signal, it shall not be
possible to change the route and move a train from another line upon the same line clear. To
avoid such a situation the last stop signal keeps the last trailing point or more trailing points
locked, which can cause the route to be changed for movement from other line. This can create
highly unsafe situation if the track between Starter and Advanced starter signal is not track
circuited.
7.3.10 Monitoring devices: Monitoring devices are used for two basic purposes one being to
monitor correspondence between operating devices and the operated equipment and secondly to
monitor status of the yard such as clearance or occupation of tracks, status of level crossing
gates, closed or open, under the control of the Satiation Master, flank protection (fouling of
adjoining track by a train standing within fouling mark) and alertness of Loco Pilot checked
through Automatic Warning system.
(A)
Devices to monitor correspondence between operating devices and operated
equipment: Any amount of Interlocking shall be infructuous if the correspondence
41
between the operating units which are levers, switches, buttons or the key board of
operating system of Solid State Interlocking and the operated equipment which are
points, point locks and signals is not established.
i)
Point and lock detectors are used to monitor setting of points for its correct housing
with the stock rail, setting for normal or reverse as the case may be and locking of
the point with full travel of the lock plunger.
ii) To monitor the status of signals, the status of signal arm is checked by a circuit
breaker attached to the arm in case of semaphore signals and by lamp checking
relays in case of colour light signals.
(B)
Devices to monitor status of the yard & systems: The interlocking between the
signals and points is established once correspondence between the operating devices
such as levers and buttons and operated equipment such as points and signals is also
established. However safe movement of the train can take place only when the line on
which the train is to be received is also checked for clearance and not fouling with any
other train standing on adjoining line, level crossing gates falling in the route of the train
which are interlocked are closed and locked against road traffic etc. It is also important
to monitor the integrity of the cable which is the media for transfer of commands from
the operating levers or panels and transferring status of the field such as correct setting
of points, aspect correspondence of signals, closure of level crossing gates etc.
i)
Monitoring clearance of the track: The devices used for checking clearance of
track are
A) Track Circuits. Different type of track circuits are used out of which most
commonly used are a) Direct Current (DC) Track circuit, b) Alternating Current
(AC) track circuits, c) Uneven Impulse (Jeomont) track circuit, d) Audi
Frequency Track Circuit (AFTC)
B) Axle counters (A/C): These devices are used depending upon specific
requirement. Track circuits shall be discussed in ensuing volume-IV of the
book.
ii) Flank Protection: The other area of safety which is required to be monitored by the
system is protection against side collisions. Two railway lines running parallel to
each other are kept at a specified minimum distance between them. If the given
distance between the two tracks is reduced, the trains running on such tracks shall
infringe with each other and shall result in side collision. Whenever two tracks join
each other through a turnout or crossover, the two tracks infringe each other till the
distance between the two is arrived at safe range. The spot at which the two tracks
become unsafe is known as fouling mark. The protection for trains on account of the
infringement of tracks is called flank protection. When the flank protection is
achieved through track circuits, the track circuits are so designed that unless the
train stands clear of the track circuit, it shall not be possible to permit the train
movement on such track (Fig 7.3.10(B-I). In yard where point zone is not track
circuited the flank protection is achieved by using fouling or clearance bars. A, 42
feet uneven angled MS bar known as fouling bar or clearance bar depending its
42
place of usage, is coupled with point in such a way that it shall not be possible to
operate the point till the Fouling or the Clearance bar is kept pressed under the
wheel. The point for the adjoining line can be set only when the fouling or clearance
bar is cleared by the train entering the berthing part of the track. Fig 7.3.10(B-II).
The fouling bar is linked with the trailing point in such a way that the point can not
be operated from its last operated position unless the last train received on main line
clears it. Similarly the clearance bar is attached to the trailing point in such a way
that it shall not be possible to operate the point unless the last rain received on loop
line clears the bar.
Fouling Mark
Clearance bar
k ci
rcu
{
T ra c
ite
da
Fouling Mark
re a
Fouling bar
Fig 7.3.10 (B-I)
Flank protection by track circuit
Fig 7.3.10 (B-II)
Flank protection by clearance and fouling bars
iii) Level crossing gates:
A)
Level crossing gate operated from the same cabin where the lever frame
is situated: The closure of level crossing gate is monitored by directly
transferring the key provided on the winch of the gate to the lock provided on
Gate locking lever in the lever frame.
B)
Level crossing gate operated from the Gate Lodge provided near the
gate: A ground lever frame is provided near the gate lodge for locking the
Boom of the gate. After the gate is closed and the boom is locked by pulling
the lever in the ground lever frame, the key is extracted from the È’ type lock
provided on lock lever, thereby holding the gate & boom by the lock lever in
reverse position, and inserted into a rotary key transmitter. The key is released
from the corresponding rotary key transmitter at the cabin where the lever
frame is placed or the panel room and applied to the gate lock lever in lever
frame or into the 2.5” stroke ‘Lever Lock’ in the Panel Room which when
operated shall make contact to prove through selection circuits that the key
has been received back after locking of the gate at site
In case of swing gates the key released from the gate leaves after locking of
the gate is interlocked with the lever frame or panel in the same way as in case
of lifting barrier gates.
The Lever Lock: mentioned here is a device equipped with ‘E’ type lock,
when key is applied & rotated in the ‘E’ type lock, its plunger makes 2.5”
movement, which is turn operates a circuit Breaker making or breaking
43
contacts to detect presence or absence of key in the ‘E’ type lock, while at the
same time the key gets locked with the ‘E’ type lock.
iv) Status of cables: Under electrical system of signalling, the operation of points,
colour light signals, detection of points, status of track circuits, proving of closing
and locking of gates or any other function, is based on the integrity of the cables laid
between the controlling cabin or Station Master’s room to the functions such as
points, signals etc. In case of the cable cut, the entire communication between
signals pints gates etc is lost and nothing much can be done to avoid such a
situation, while damage to the cable which usually results in seepage of water inside
cable jacket or damage to cable core insulation shall result in shorting/earthing of
cable conductors, which in turn may lead to extending false feed to the relay or
signal lighting, creating unsafe situation. The Earth Leak Detector (ELD) is
therefore used for continuous monitoring health of the cable. Usually spare
conductors of the cable are connected to ELD which in turn detects loss of
insulation of the conductors with respect to earth.
7.4
Isolation: When trains move on the track the Loco Pilot has no liberty to steer away his
train to protect it from a train which may be fouling its path. To ensure that the moving train
does not make a side collision, the junction of crossovers/ turnouts are marked at the position
where two tracks come so close so as to foul the adjoining track and may result in side collision.
These marks are known as fouling marks. The trains are supposed to stand having cleared these
fouling marks after negotiating the crossover or turnout, before a movement to other train is
permitted on the same track for a different route so that the other train does not make a side
collision. To avoid this to happen the conflicting junctions are required to be Isolated. This is
called as isolation. With reference to Indian Railways, Isolation means an arrangement, secured
by setting of points or other approved means to
Trap Point
protect the line so isolated from the danger of
obstruction from other concerned line or lines.
[GR1.01 (32)].
Fouling Mark
Fig. 7.4
Isolation by trap point
7.4.1
i)
ii)
On interlocked stations the isolation is ensured
through various means as provided in Signal
Engineering manual detailed as follows:
Isolation where to be provided:
At Block station where trains are permitted to run at speeds in excess of 50 Kilometre
per hour, the line on which the speed is permitted shall be isolated from all connected
lines during the passage of the train.
The isolation shall not be required to be provided on block stations on which speed
permitted is 50 Kilometre per hour or less provided all shunting has been stopped and
no vehicle which is not attached to an engine or not properly secured by the Station
Master in accordance with approved special instructions, has been kept standing on a
connected line which is not isolated from the through line.
44
7.4.2
i)
ii)
iii)
iv)
v)
vi)
Means of Isolation: The isolation is achieved through one of the following means:
[SEM 1988 Para: 7.72 ]
Sand hump, trap points or any other approved means of isolation shall be provided on
all goods lines and sidings at their junctions with passenger lines, the normal setting
being such as to prevent the passenger lines from being fouled.
On interlocked stations the means of isolation shall be interlocked.
In order to maintain safety the trap points shall not be inserted on main or run through
lines.
However an exception be allowed under approved special instructions in case where
owing to grades in or near stations it is necessary to prevent i) trains being brought to
stand at a Stop Signal on a rising grade or ii) vehicles running away from the station.
Also an exception may be allowed under approved special instructions, where it is
considered necessary in the interest of working to receive trains from opposite direction
simultaneously.
At stations where trap sidings are inserted on main lines, through running of the trains
shall be permitted only under approved special instructions.
7.5
Overlap: On Indian railways system of working, a pre determined distance beyond the
next stop signal is required to be kept clear before taking ‘Off’ any signal, to maintain safety in
case the train gets out of control and overshoots beyond the next signal to which the train is
approaching. This adequate distance is called overlap.
In case of signal to be taken ‘Off’ is within station section the overlap to be kept clear ahead on
next signal on the same station is called signal overlap and if the train is leaving the last stop
signal of station to approach the first stop signal of the station in advance, the overlap to be kept
clear beyond first stop signal at the next station is called Block overlap. The adequate distance
for Signal overlap and the Block overlap are different in case of two aspect signalling section
and multiple aspect signalling section as follows:
7.5.1 Signal overlap: In case of two aspect signalling territory, Signal Overlap shall be 180
metres, while in case of Multiple Aspect signalling territory it shall be 120 metres.
7.5.2 Block overlap: In case of two aspect signalling territory Block Overlap shall be 400
metres, while in case of Multiple Aspect signalling territory it shall be 180 metres.
8.
Block Working: The definition of the station as given in the General rules [GR
1.02(51)] reads that: ‘any place on a line of railway at which traffic is dealt with or at which an
authority to proceed is given under the system of working’. Under the chapter of systems of
working it is prescribed that The Absolute Block and Automatic Block system alone shall be
used on every railway, except on any railway or portion of railway on which the use of any other
system of working, as mentioned in the GR, may be sanctioned under special instructions.
On sections where Absolute Block system of working is in use, an authority to proceed is
required to be given to the Loco Pilot for leaving the station. The stations on either end of the
block section are called Block Stations. In this system of working only one train is allowed to be
in the block section at one time. The second train is allowed to leave the station only when the
45
first train has reached the next station and all conditions to grant line clear to the following train
have been fulfilled. The authority to leave the Block Station can only be given by stopping every
train at the station which is an impractical proposition. Uninterrupted running of trains between
two Block stations is mechanised and regulated by any one or combination of the following
means:
8.1
Electrical Block Instruments of Token or Token-less type: On double line section,
only token-less type of block instruments are used. On single line section Token less or Token
block instruments are used. Complete arrival of the train i.e. Last vehicle check is required t o be
done manually with the use of these Block Instruments.
8.2
Track circuits: Continuous track circuits covering the entire Block section is one of the
best methods of Block working as it automatically covers the complete arrival of train. There
being a restriction of 350 metres length of Direct Current (DC) track circuits on PRC sleepers,
the maintenance of huge number of track circuits on lengthy Block sections, is quite difficult. As
such this method of Block Working is used on smaller block sections ranging between 1to2 km.
only. However with the introduction of lengthier Audio Frequency Track Circuits (AFTC), with
an added advantage of joint less track circuiting, are being used on important routes with longer
block sections also.
8.3
Axle counters: Axle counters are one of the electronics alternatives to DC track circuit
or AFTC. The use of Axle counters also covers the complete arrival of trains. This system is
known as Block Proving by Axle Counters.
8.4
Electrical Communication Instruments: In case of failure of Block instruments, the
Line clear can also be obtained through telephones attached with the Block instruments, station
to station fixed telephones and other fixed telephones such as Railway Auto phones & BSNL
phones, control phones or VHF sets. However the last stop signal, which is interlocked with the
line clear, shall not be possible to be taken ‘Off”, the train shall have to be brought to stop for
issue of ‘Authority to Proceed’ before permitting it to leave the station.
9.
Sidings: To cater for situations where an axle of any wagon or coach of the train
becomes hot or for any other reason it is not possible to carryon the train with the vehicle and
the vehicle is required to be detached from the train and kept at the intermediate station, short
sidings are provided with a trap in the form of a derailing Switch at such stations. Sidings are
also provided on stations to facilitate shunting or private sidings taking ‘Off’ from the station to
the premises of factory, oil depot etc or to meet with other safety requirements. These sidings
are broadly classified in two groups:
9.1
Trap siding: For stabling of vehicles or leading to private sidings provided with trap to
safeguard against unauthorised or unwanted escaping of vehicle so as not foul the running line.
Such sidings are termed as trap sidings.
9.2
Catch siding and Slip siding: On hilly area where railway track is having steep
gradients, the failure of brake of the train or detachment of a vehicle from the running train can
lead to rolling of the train or detached vehicle to the adjoining station placed on lower level and
46
hit a train /vehicle standing there. To safe guard against such a situation, at a station where there
is a gradient of 1 in 80 falling towards the station or 1 in 100 falling away from the station
within 45 metres beyond the outermost points at either end, a catch siding in case of 1 in 80
falling towards the station and a slip siding in case of 1 in 100 away from the station should be
provided.
As the names suggest a Slip siding is meant to take care of a vehicle slipping away from the
station preventing its entry into the block section and a catch siding is meant to take care of a
vehicle rolling from the block section to enter into the catch siding instead of entering into the
station section.
Normally the spring loaded points are kept set for Catch or Slip siding and are set and locked for
reception or despatch of a train whenever a train movement is to take place
The track for these sidings is laid gradually increasing to a gradient upper than the station, of
sufficient length so as to stop the lose vehicle or train of itself due to gravitational forces,
without damage.
10.
Level Crossing Gates: A road crossing the railway track at the same level as the track
has to be protected by a gate. These gates are known as Level Crossing Gates. The level crossing
gates may be manned or unmanned. Here only manned level crossing gates are discussed. The
level crossing gates may fall within the Station Section, station limits or Block section.
10.1
Classification based on TVUs: The gates are classified as `Special‘class, À’ class, `B’
class and `C’ class. The classification of the gates is done in consultation with road authorities,
on the basis of class of the road, visibility conditions, volume of road traffic across the gate and
number of trains passing over the level crossing. These details are prepared based on census
done for one week. The census is done at least once in five years and the classification of the
gate is revised based on such census, if required. All such criteria are converted into `Train
Vehicle Unit’ (TVU) taking train, motor vehicles, bullock carts and tongas as one unit and cycle
rikshaw/auto rikshaw as ½ unit. Number of these units for the gates decides the classification of
the gate as tabulated below: [IR P Way Manual Para 919]
SN
1.
2.
3.
4.
Class of the level crossing
`Special’ class
À’ class
`B’ class
`C’ class
Criteria
TVUs > 50,000
TVUs between 30,000 and 50,000.
TVUs > 20,000
All other level crossings not covered above
10.2
Classification based on management of the level crossing gates: All level crossing
gates falling within station limits are managed by the Operating department and are called as
Operating gates. The gates falling in the block section are managed by Engineering department
and are called as Engineering gates. The management of the gate includes provision of staff,
equipment and Accessories. The gates which are interlocked and provided with Lifting Barriers
are maintained by S&T department, while all types of the gates which are non-interlocked and
47
interlocked gates provided with swing leaves are maintained by Engineering department. The
interlocking part of swing gates is managed by S&T department.
10.3
Interlocking of level crossing gates (Railway Board’s Circular number 2000/Sig/LX/
2/Pt. Dated 5.5.2003):
10.3.1 Interlocking of `Special’ & À’ class level crossing gates:
A) Within Station Limits: All Special’ & À’ class level crossing Gates, falling within
station Limits are required to be:
i) Interlocked,
ii) Where the level crossing gate is operated from a place other than place of operation
of the signal protecting the gate, arrangement of interlocking should be such that the
last operation before taking the signal ‘Off’ should be closing of the gate and first
operation after the train has cleared the gate and the signal has been put back to
Òn’, should be opening of the gate by the gateman.
iii) Normally open to road traffic,
iv) Provided with lifting barriers,
v) Provided with telephone communication with ASM’s office.
B) Out side station Limits: All Special’ & À’ class level crossing Gates, falling out
side station Limits are required to be:
i) Interlocked,
ii) Warning Bell operated by the approach of train shall be provided on `Special ‘ class
gates. However in case of À’ class gates warning bell shall be provided on
suburban or Automatic Block signalling sections while at other sections individual
railways my provided this facility as and where considered desirable,
iii) Normally open to road traffic,
v) Provided with telephone communication with ASM’s of the adjoining station.
10.3.2 Interlocking of ‘B’ class level crossing gates:
A) Within Station Limits: All `B’ class level crossing Gates, falling within station
Limits are required to be:
i) In suburban section, Interlocked,
ii) In non suburban section where the gates are operated by cabin staff of cabins
adjoining the level crossing gate, the level crossing gate should be interlocked with
the station signals,
iii) Normally closed to road traffic,
v) Provided with telephone communication with ASM’s office.
B) Outside Station Limits: All `B’ class level crossing Gates, falling out side station
Limits on sections other than Automatic Block Signalling are required to be:
i) In suburban section, Interlocked,
ii) Normally closed to road traffic,
iii) Provided with lifting barriers,
48
iv) Provided with telephone communication with ASM’s of adjoining station on
Rajdhani Express routs and on suburban sections. On other routes such
communication shall be provided at those level crossing gates which are situated on
curves obstructing the view of the level crossing from the approaching train or vice
versa.
10.3.3 Interlocking of ‘C’ class level crossing gates:
A Within Station Limits: All `C’ class level crossing Gates, falling within station
Limits are required to be:
i) Where the gates are operated by cabin staff of cabins adjoining the level crossing
gate, the level crossing gate should be interlocked with the station signals,
iii) Provided with telephone communication with ASM’s office.
B Outside Station Limits: All `C’ class level crossing Gates, falling out side station
Limits on sections other than Automatic Block Signalling, are required to be:
i) Action shall be taken to upgrade such Level crossing gates on suburban section to
upgrade them to `Special’ or À’ class. Till the gates are upgraded, provisions of
‘Special’/’A’ Class gates shall be made. If these gates do not qualify for up
gradation to `Special’ or À’ class based on TVUs, these may be considered for up
gradation to `B’ class and provisions of `B’ class gates shall be done.
iii) Provided with telephone communication with ASM of adjoining station on Rajdhani
Express routs and on suburban sections. On other routes such communication shall
be provided at those level crossing gates which are situated on curves obstructing
the view of the level crossing from the approaching train or vice-versa.
10.4
Level crossing gates falling in the section provided with Automatic Block
signalling: All level crossing gates falling in the Automatic Block signalling section
shall be:
i) Interlocked irrespective of its class,
ii) Provided with warning bell operated by approaching trains,
iii) Approach locked.
11.
Schedule of Dimensions (SOD): Signalling equipment are provided indoors and
outdoors both. Outdoor equipment are installed by the side of the track preferably as near as
possible such as signal posts, point machines and track lead junction boxes; In between two rails
viz. facing point locks, Automatic Warning System (AWS) equipment; Equipment attached to
track viz. lock bars, holding bars, Axle counter transducers; And some systems superimposed on
the rails such as DC track circuits, AC track circuits, Audio frequency track circuits, Jeomont
track circuits etc. To ensure that these equipment do not infringe with the moving train, a
Schedule of Dimensions is issued by the Railway Board.
The gauge of the track is measured between inner faces of both rails forming the track. There are
three gauges of track in prevalent on Indian railways, the Broad gauge 1676 mm (5 feet.6
inches), Metre gauge (3 feet 3.3 inches) and narrow gauge 610 mm (2 feet 0 inch) besides tracks
on hilly terrain with special gauge.
49
The schedule of dimensions was issued by Railway Board in 1922 in Foot Pound Second (FPS).
These schedules of dimensions were in two parts one was schedule of maximum and minimum
dimensions and other was schedule of recommended dimensions. In 1926 Railway Board gave
directions that schedule of recommended dimensions shall be followed in all future works and
alteration to new works. These orders were modified on 26th April 1926 allowing relaxation in
case of certain recommended dimensions which involved heavy expenditure in remodelling
work. Major changes were done in schedule of dimensions issued in 1939 and there have been
reprints thereafter. The SOD is therefore is known as SOD 1939. With the change in
measurement scale system from (FPS) to Metre Kilogram Second (MKS), the gauges of the
track were also converted to MKS in1964.
The Schedule of Dimensions 1973 version was based on requirement of 25KV AC traction and
all future works were to be carried out to these dimensions except in cases where it was
considered that there was no chance of the line being subsequently converted to 25 KV AC
traction.
The present Schedule of Dimensions (Revised, 2004) is revised version of Schedule of
Dimensions 1939 reprinted in 1973. This schedule is only metric units. In this only two
schedules have been kept.
Schedule-I consists of those items which are mandatory and have to be observed on all 1676mm
Gauge railways in India. It is mandatory and contains the items of schedule –I & certain selected
items of Schedule-II of 1973 version.
Schedule-II consists of items included in Schedule-III of 1973 version. These items contain the
infringements to dimensions prescribed in Schedule-I, which may, subject to restrictions of
speed as considered necessary, be permitted on existing railways with the understanding that
when structures are altered they will be rebuilt to comply with Schedule-I, except in case of
dimensions of `building and structures, chapter -I, `General’ of Schedule of dimensions 1676mm
Gauge (revised 2004), Item A, 2 of the table given below. Dimensions under Schedule-II have
not been dealt with here.
It is important to note that the dimensions show minimum clearance from the track centre as
such are measured between track centre and outermost edge of the equipment being installed.
The dimensions are applicable to fixed structures only.
The schedule of dimensions for broad gauge 1676 mm (5 ft.6 in. Gauge) track (BG) are
tabulated below:
SN Equipment
Existing
New
works
works
A
Dimensions in General
1
Spacing of Tracks
Minimum distance between centre to centre of tracks
4265mm
5300mm
2.
Building & structures:
2.1 Minimum horizontal distance from centre of track to any
1675mm
1905mm
50
2.2
i)
ii)
iii)
structure from rail level upto 305mm above rail level
Minimum horizontal distance from centre of track to any
structure except a platform
From 305mm above rail level to 4420mm above rail level
2135mm
--
1905mm
increasing
to 2360mm
2360 mm
From 1065 mm above rail level to 3355mm above rail
level
level
--
v)
level
--
vi)
Below the rail level up to the formation level of the track - on straight and curves upto radius of 875m
Below the rail level up to the formation level of the track - 2725mm
on straight and curves with radius less than 875m
Note:
1. With reference to spacing of tracks new /additional works cover laying of new lines
and new running loops. Extension of existing line or replacement of points &
crossings will not be treated as new work.
2. Under item number 2.1 &2.2 as above, any material stacked by the side of line is to
be considered a structure in the sense in which the word is used here. These items
also apply to projections of rock etc., from the side of cutting.
3. Light structures such as ladders, thin posts etc erected along side the track at a
distance of less than 2360mm from centre of the adjacent track should be blanked
off to a height of 300mm between 2060mm and 2360mm above rail level.
4. Required clearances as mentioned in items vi) & vii) above, will be applicable in
case of new lines/doubling/electrification.
5. Various fixtures which are attached to the track like traction bonds etc. and are
required to be fitted with the rail can be provided and the clearance as
mentioned in items vi) & vii) above will not be applicable to these fixtures.
6. Item 2.2 is applicable for the structures out side station yards.
Minimum horizontal distance of any telegraph post
The height The height
of the post
measured from the centre and right angles to the nearest
of the post
plus
track.
plus
2360mm
2315mm
Note: When the line is cutting a telegraph post erected outside the cutting, must be at
a distance from the edge of the cutting not less than the total height of the post.
Interlocking and signal gear:
Maximum height above rail level of any part of
64mm
-interlocking or signal gear for a width of 1600mm or
1830mm in case of tunnels, through and semi-through
iv)
vii)
3.
4
51
--
2360 mm
decreasing
to 2135mm
2135mm
decreasing
to 915mm
2575mm
B
1
2
C
1
2
a)
girder bridges on either side of centre of track subject to
the restriction embodied in the note (a) below:
Note:
(a) For distance of 229mm outside and 140mm inside the gauge faces of the rail, no
gear or track fittings must project above rail level except such parts as are required to
be actuated by the wheels or wing rails and point rails of special crossing leading to
snag dead ends or elevated ends or elevated check rails of crossing or check rails/check
flats of diamond crossings.
(b) Signal wires or supports for signal wires may be allowed at not less than 1600mm
or 1830mm in the case of tunnels or through or semi through girder bridges on either
side of the centre of track provided that they are not more than 203mm above rail level.
(c) Metal covers with ramps on both sides must be provided over all interlocking gear
projecting above rail level between the rails of a track to prevent hanging couplings
from damaging the gear.
Tunnels, through & semi through girder bridges:
Track centre
4495mm
4725mm
Minimum horizontal distance from centre of track to any structure shall be as follows:
(a) Height above rail level from 0.0mm to 305mm
1905mm
-(b) Height above rail level from 305mm to 1065mm
1905mm
-increasing
to 2360mm
(c) Height above rail level from 1065mm to 3355mm
2360mm
-(d) Height above rail level from 3355mm to 4420mm
2360mm
-increasing
to 2135mm
(e) Height above rail level from 4420mm to 5870mm*
2135mm
-decreasing
to 915mm
*Where D.C. electric traction is in use height above rail
2135mm
-level from 4420mm to 5410mm shall be
decreasing
to 915mm
Station yards
Station limits, as defined under GR1.02 (52) shall be taken into consideration for the
purpose of station yard.
Spacing of Tracks
4265mm
5300mm
New /additional works cover laying of new lines. Extension of existing line or
replacement of points & crossings will not be treated as new work
Maximum gradient in station yards unless special
1 in 400
1 in 1200
safety devices are adopted and/or special rules enforced to
prevent accidents in accordance with approved special
instructions.
It may not be possible to provided yard gradients of 1 in 1200 while executing works
in connection with gauge conversion, doubling and new crossing station etc. Railway
52
b)
c)
d)
e)
f)
1
i)
ii)
iii)
iv)
2.
should, however make effort to provide grades as flat as possible in the station yards
but not steeper than 1 in 400. In case gradient steeper than 1 in 400 are required to be
provided in exceptional cases, condonation for the same should be obtained from
Railway Board
For the purpose of above rule a station yard shall be taken to extend:
i) On single line to a distance of 50 meters beyond outermost points at either end of the
station.
ii) On double line where two aspect signalling is provided, from Home signal to a
distance of 50 meters beyond outermost facing points at the trailing end, or where
there are no lops, to the last stop signal of each line.
iii) On double line where multiple aspect signalling is provided, to a distance 50 meters
beyond outermost points at either end of the station or where there are no loops,
from Block Section Limit Board to last stop signal of each line.
No siding should join a passenger line on a steeper grade than 1 in 260, except where it
is unavoidable and then only with the previous sanction of the Railway Board obtained
through Commissioner of Railway Safety when slip siding or any other arrangement is
made sufficient to prevent accidents.
Except in Hump or Gravity yards or provisions of adjustment of super-elevation in
item 22 of chapter –II of Schedule of Dimensions revised 2004, there must be no
change of grades within 30 meters of any points or crossings.
At stations with grades steeper than 1 in 400 beyond 45m (150 ft) of outermost points,
trains should not be drawn upto last stop signal and held up on steep gradient in order
to clear the reception line for giving permission to the following train.
No shunting beyond outermost points on the steep gradient side should be allowed
unless a locomotive is attached at the lower end of the lead from the point of view of
gradients
This item does not apply to flag or Halt stations.
Building and structures
Minimum horizontal distance of any building on a passenger platform from centre
line of track:
From platform level to 305mm above rail level
5180mm
-increasing
to 5330mm
From 305mm above platform level to 3430mm above
5330mm
-3430mm above rail level
From 3430mm above platform level to 4115mm above rail 5330mm
-level
decreasing
uniformly
to 3810mm
From 3430mm above platform level to 4610mm above rail - 5330mm
level
decreasing
uniformly
to 3810mm
Minimum horizontal distance of any building or longi5485mm
10210mm
tudinal boundary fence from the face of the platform
53
3.
i)
ii)
iii)
iv)
4.
i)
ii)
iii)
iv)
5.
i)
ii)
coping of passenger platform which is not on island
platform (for new works or alteration to existing work)
Note: This also shall apply o buildings and isolated structures not readily removable,
erected on ground over which it is anticipated that a platform may be extended in
future.
Minimum horizontal distance from centre line of track to pillar, column, lamp or
similar isolated structure on a passenger platform or any building on a goods
platform.
-From platform level to 305mm above platform level
4570mm
increasing
uniformly
to 4720mm
-level
From 3705mm above rail level to 4115mm above rail
4720mm
-level
decreasing
uniformly
to 3810mm
-4720mm
level
decreasing
uniformly
to 3810mm
Minimum horizontal distance from centre line of track to pillar, column, lamp or
similar isolated structure on a goods platform.
From platform level to 305mm above platform level
39600mm
-increasing
uniformly
to 4110mm
-level
-From 3980mm above rail level to 4115mm above rail
4110mm
level
decreasing
uniformly
to 3810mm
-4720mm
level
decreasing
uniformly
to 3810mm
Note: A pillar or column, with reference to item numbers 3 & 4 above, which covers
more than 3716sq.cm. in plan, must be classed as `building’ and not as an ìsolated
structure’.
Minimum horizontal distance from centre of track to any
structure:
From rail level to 305mm above rail level
1675mm
1905mm
From 305mm above rail level to 1065mm above rail level - 1905mm
54
iii)
iv)
v)
From 1065mm above rail level to 3355mm
level
vi)
level on main line
level
vii)
-2135mm
2135mm
decreasing
to 1980mm
1600mm
--
--2360mm
decreasing
to 135mm
2315mm
decreasing
to 1980mm
1600mm
viii
level
ix)
-level
Below rail level upto the formation level of the track on
2725mm
-curves with radius less than 875mm
Minimum clearance between toe of open switch and stock 95mm
115mm
rail
Minimum length of train protection, point locking or
12800mm
-fouling treadle bar.
Note: This includes lock bar, fouling bar and holding bar.
Dimensions of carriage and wagons
Minimum projection for flange of new tyre , measured
28.5mm
-from tread at 63.5mm from wheel gauge face
Minimum projection for flange of worn out tyre ,
35.0mm
-measured from tread at 63.5mm from wheel gauge face
Maximum thickness of flange of tyre, measured from
28.5mm
-wheel gauge face at 13mm from outer edge of the flange.
Minimum thickness of flange of tyre, measured from
16.0mm
-wheel gauge face at 13mm from outer edge of the flange.
Maximum distance apart between any two adjacent axles. 12345mm
-Dimensions of Loco motives:
Thickness of tyre flange measured at 13mm from edge of the flange
Thick flange
32mm
-Standard flange
28mm
-Thin flange
18mm
-DC traction- Minimum distance between live conductor
130mm
-wire and any structure
25KV AC traction- minimum vertical distance between any live bare conductor
(overhead equipment or pantograph) and any earthed structure or any other bodies
(rolling stock, over bridges, signal gantries)
When conductor is at rest
320mm
--
x)
6.
7.
8.
i)
ii)
iii)
iv)
v)
9.
i)
ii)
iii)
10
11
i)
55
--
increasing
to2360mm
2360mm
ii)
When conductor is not at rest
270mm
-Note: For extra clearances on curves appendices to Indian Railways Schedule of
Dimensions 1676mm gauge (BG) 2004 shall be refereed to.
Split stretcher bars connecting the tongue rails for keeping the points locked, while passage of
train, when hit by hanging coupling, disturb the adjustment and when broken having hit hard
leave the point unlocked. As such, even though the entire arrangement does not protrude above
rail level, it is safe to provide the cover with ramps on both sides.
*****
56
Chapeter II Self Assessment
1. Multiple Choice Questions:
1
2
3
4
5
Approved special instructions are approved
by:
a) Commissioner of Railway Safety*
b) Authorised officer
c) Any one of them
d) None of them
As per SOD recommended placement of
signal post from centre of track is(mm):
a) 1905
b) 2315*
c) 1675
d) 2360
Mounting of track devices of axle counters
on rail, do not infringe schedule of
dimensions because:
a) No body bothers fixing any thing on
rail web or flange
b) There is a provision in SOD*
c) The provision is approved under
special instructions
d) It does not come in physical contact
wheel
Correspondence between operating units i.e.
levers & buttons and operated units i.e.
points & signals is essential to ensure that:
a) Signal is ‘On’ when lever is normal*
b) Signal is ‘Off’ when lever is normal
c) Pulled signal is ‘On’ when lever is
reverse
d) All of above
Dead approach locking is locking provided to
hold the route when:
a) The signal is dead with no light
b) When there are no track circuits on the
section of track on which train is
approaching or standing*
c) When the train has crossed the signal
d) None of above
6
Signal overlap is 120 meters in:
a) Two aspect signalling territory
b) Three aspect signalling territory*
c) Semaphore signalling territory
d) None of them, It is Block overlap instead
7 Stations can be classified as:
a) Block Stations
b) Non Block Station
c) Both of above*
d) None of above
8 Component of TVUs is/are:
a) Train, motor vehicle, bullock carts &
Tongas
b) Cycles, rickshaw, auto rickshaw
c) All of them*
d) None of them
9 Back locking is locking provided to hold the route
when:
a) The train has crossed the signal*
b) When the train is being pushed back
c) When the train has stopped near the foot of
signal
d) None of above
10 Shunt signal on a post of a running signal
displays:
a) Two lights to form horizontal line to show
‘On’ aspect
b) Two lights to form a line include to 45º to
horizontal to show ‘Off’ aspect with main
signal showing ‘On’ aspect*
c) Two lights to form a line include to 45º to
horizontal to show ‘Off’ aspect with main
signal showing ‘Off’ aspect
d) Two lights to form horizontal line when
signal is ‘On’ & include to 45º to
horizontal when the signal is ‘Off’ with
main signal showing ‘On’ aspect
57
2. Select the right answer True/False:
1.
2.
3.
4.
5.
6.
7.
8.
9.
Station Section & Station Limits are the same thing. True/False*
Colour light signals work in two aspect signalling system also. True*/False
There is upper speed limit in case of standard IV interlocked station. True*/False
Means of isolation need not be interlocked with signals. True/False*
Loco pilot must obtain permission to enter the Block section. True*/False
On ‘A’ class station the Block Section & Station Section overlap each other. True*/False
Intermediate Block Post can be created on single line section also. True/False*
A ‘C’ class station is Non Block station. True/False*
A calling-on signal can be taken ‘Off’ simultaneously with the main signal on the post of which the
signal is provided. True/False*
10. In a lever frame the lever pulled last is always that of a signal. True*/False
11. ‘Red’ light of the signal is called as Red aspect. True/False*
12. All level crossing gates in automatic signalling territory irrespective of their classification shall be
interlocked. True*/False
3. Answer the following questions:
1.
2.
3.
4.
5.
Please give signalling requirements at station interlocked to standard IV with reference to isolation,
signalling, point operation, point locking, point &lock detection, interlocking, track circuit and Block
working.
Please define Station section & Block section on multiple aspect signalling system provided on double
line section. Elucidate your reply supported by diagram.
Please detail the procedure of passing a gate signal at danger in Automatic Block Signalling section.
Discuss essentials of interlocking. Bring out methods of implementing the provisions thereof, briefly.
How can back locking be achieved by mechanical means? Elucidate your answer supported by
sketches wherever needed. Can approach locking be achieved by mechanical means if yes how. How
approach locking can be achieved otherwise.
*****
58
CHAPTER –III
SYSTEMS OF WORKING ON INDIAN RAILWAYS
1
Systems of Working the trains: As per General Rule [GR 7.01] the System of
Working is defined as, “the system adopted for the time being for the working of trains on any
portion of a railway”.
The trains are worked on any one of the six systems of working on Indian railways which are Absolute Block system, Automatic Block system, Following train system, Pilot Guard system,
Train – staff and Ticket system, or One Train only system.
Out of these systems only Absolute Block System and Automatic Block Systems are specified to
be used on Indian Railways while other systems of working shall be used under special
circumstances as authorised by Railway Board. As per chapter VII of General Rule Book of
Indian railways “The Absolute Block and Automatic Block systems alone shall be used on every
railway, except any railway or portion of a railway on which the use of any other system of
working mentioned in sub rule may be sanctioned under special instructions subject to the
conditions applicable to each system as described in these rules”.
2.
Absolute Block system: Under Absolute Block System, the trains are run in such a
manner that there is only one train on each line, in between two stations. There is no agency to
monitor running of trains in between two stations except the train crew, as such the systems of
working are designed by framing set of rules for running of trains between two stations.
As per General Rule book [GR8.01] of Indian Railways, under this system of working:
i)
ii)
iii)
iv)
No train shall be allowed to leave a Block station unless Line clear has been received
from the block station in advance; and
On double lines such Line Clear shall not be given unless the line is clear, not only up
to first stop signal at the Block Station at which such Line Clear is given, but also for an
adequate distance beyond it;
On single line such Line clear shall not be given unless the line is clear of trains running
in the same direction, not only up to first stop signal at the Block Station at which such
Line Clear is given, but also for an adequate distance beyond it , and is clear of trains
running in the direction towards the block station to which such Line Clear is given;
The adequate distance so mentioned above shall under normal circumstances be not less
than:
a) 400 metres in case of two-aspect lower quadrant signalling or two- aspect colour
light signalling, and
b) 180 metres in case of multiple aspect signalling or modified lower quadrant
signalling.
59
Conditions for granting Line clear at a class À’ station: [GR 8.02] At À’ class
2.1
station on single line or on double line, the line shall not be considered clear and Line clear shall
not be given, unless:
2.1.1
2.1.2
2.1.3
2.1.4
The whole of the last preceding train has arrived complete;
All signals have been put back to Òn’ behind the said train;
The line on which it is intended to receive the incoming train is clear up to the Starter;
and
All points have been correctly set and all facing points have been locked for the
admission of the train on the said line.
2.2
Conditions for granting Line Clear at a class `B’ station on double line: At a class
‘B’ station on double line, the line shall not be considered as clear and Line clear shall not be
given, unless:
2.2.1
2.2.2
2.2.3
All necessary signals have been put back to Òn’ behind the said train; and
The line is clear:
(i) At stations equipped with two aspect signalling: Up to Home signal, or
(ii) At stations equipped with multiple aspect signalling or modified lower quadrant
signalling- up to the outermost facing point or the Block section Limit Board (if
any).
2.3
Conditions for granting Line Clear at a class `B’ station on single line: [GR 8.03]
The line shall not be considered clear and the Line Clear shall not be given unless:
2.3.1
2.3.2
2.3.3
All necessary signals have been put back to Òn’ behind the said train; and
the line is clear:
a) At stations equipped with two aspect signalling:
• Up to Shunting Limit Board or Advanced starter (if any) at that end of the station
nearest to the expected train, or
• Up to the Home Signal if there is no Shunting Limit Board or Advanced starter, or
• Up to the outermost facing point if there is no Shunting Limit Board or Advanced
starter or Home Signal;
b) At stations equipped with multiple aspect signalling or modified lower quadrant
signalling:
• Up to Shunting Limit Board or Advanced starter (if any) at that end of the station
nearest to the expected train, or
• Up to the outermost facing point if there is no Shunting Limit Board or Advanced
starter.
2.4
Direct reception of a train from one side: when Line Clear has been given to the
block station on the other side; At a class `B’ single line station, above conditions do not forbid
direct reception of a train from one side, when Line Clear has been given to the block station on
60
the other side provided the distance between the Outer signal and outermost facing points in two
aspect signalling, and between the Home signal and outermost facing point in multiple aspect
signalling or modified lower quadrant signalling is not less than the sum total of adequate
distances prescribed in rule for granting line clear and rule for conditions for taking ‘Off’ Home
signal.(Fig.2.4).
HOME
OUTER
WARNER
STARTER
OUTER
WARNER
HOME
STARTER
Fig.2.4
Conditions for direct reception of train, on a single line `B’ class station with two aspect
signalling, from one side when line clear is already granted to other side
2.5
Conditions for granting Line Clear at a class `C’ station: [GR 8.04] At a class `C’
station on single or double line in two aspect, multiple aspect or modified lower quadrant
signalling the line shall not be considered clear and Line clear shall not be given, unless:
2.5.1 The whole of the last preceding train has passed complete at least 400 metres beyond the
home signal and is continuing its journey; and
2.5.2 All signals taken Òff ‘ for the preceding train have been put back behind the said train;
provided that on a single line, the line is also clear of trains running in opposite direction
towards the Block Hut from the Block station at the other end.
2.6
Obstruction on a block station on double Line section when a train is approaching
the station: [GR 8.05]
2.6.1 Class À’ station: When Line Clear has been given, no obstruction shall be permitted
outside the Home signal, or, on the line on which it is intended to admit the train, up to the
starter pertaining to the said line.
2.6.2 Class `B’ station: When Line Clear has been given, no obstruction shall be permitted
outside the Station Section but shunting within the station section may go on continuously,
provided the necessary signals are kept at Òn’. When signals have been taken Òff’ for an
approaching train on a line, which is not isolated, no shunting movement shall be carried out
towards the points over which the incoming train will pass.
2.7
Obstruction on double line, in the block section: [GR8.06]
2.7.1 When Line Clear has been given, no obstruction shall be permitted in the block section
in rear.
61
2.7.2 Shunting or obstruction for any other purpose shall not be permitted in the block section
in rear unless it is clear and blocked back.
2.7.3 Shunting or obstruction for any other purpose shall not be permitted in the block section
in advance unless it is clear and is blocked forward:
Provided that when the block section in advance is occupied by a train travelling away from the
station, shunting or obstruction may be permitted behind the train under special instructions
taking into consideration the speed, weight and brake power of the train and the gradients on the
section, and as soon as intimation has been received that the train has arrived at the block station
in advance, the line shall be blocked forward if it is still obstructed.
Block back or Block forward shall be done in accordance with the procedure prescribed by
special instructions.
2.8
Obstruction on single line in block section:
Class À’ stations
2.8.1 Obstruction on single line at a class À’ station when train is approaching :
[GR 8.07] when Line Clear has been given, no obstruction shall be permitted outside the Home
signal, or, on the line on which it is intended to admit the train, up to the Starter which controls
the train.
2.8.2 Obstructing the block section at a class À’ station on single line: [GR8.08] The
block section shall not be obstructed for shunting purposes, unless:
i)
The Station Master has received Line Clear from the Station Master at the other end of
the block section, or
ii)
The Block Section is blocked back, or
iii)
Is occupied by a train travelling away from the block station at which the shunting is to
be performed which shunting may be permitted under special instructions taking into
consideration the speed, weight and brake power of trains and gradients on the section.
As soon as intimation has been received that the train has arrived, the block section shall
be blocked back, and
iv)
The Loco Pilot or other person in charge of the shunting operation has received distinct
orders from the Station Master to shunt in a manner directed by special instructions.
2.8.3 Obstruction in face of an approaching train at a class `B’ station on single line:
[GR 8.09] The line outside the Home signal in two-aspect signalling territory or facing point in
multiple aspect or modified lower quadrant signalling territory in the direction of a train for
which line Clear has been given, shall only be obstructed when a Shunting Limit Board or
Advanced starter signal is provided and under special instructions which take into consideration
the speed, weight and brake power of train, the gradients, the position of first Stop signal and the
distance from which that signal can be seen by Loco Pilot of an approaching train.
2.9
Obstruction within station section at a class `B’ station on single line: [GR 8.10]
2.9.1 If the necessary signals are kept at on shunting may be carried on within the station
section, provided the provisions of paragraph 2.8.3 of this chapter as given above, are complied
with for shunting up to Shunting Limit Board or Advanced Starter, where provided.
62
2.9.2 When signals have been taken ‘Off’ for an incoming train on to a line, which is not
isolated, no shunting movement shall be carried on towards the points over which the incoming
train will pass.
2.10
Obstructions outside station section at a class `B’ single line station equipped with
two-aspect signals: [GR 8.11]The line outside station section and up to Outer signal shall not be
obstructed unless a railway servant specially appointed in this behalf by the Station Master is in
charge of the operations, and unless:
2.10.1 The block section into which the shunting is to take place is clear of an approaching
train and all relevant and necessary signals are at on position, or
2.10.2 If an approaching train has arrived at Outer signal, the Station Master has personally
satisfied himself that the train has been brought to a dead stand at the signal, provided that the
line shall not be obstructed under this para, in thick, foggy or tempestuous weather impairing
visibility or, in any case unless authorised by special instructions.
2.11
Obstructions outside station section at a class `B’ single line station equipped with
manually operated multiple aspect signals: [GR 8.12] The line outside station section and up
to first stop signal shall not be obstructed unless a railway servant especially appointed in this
behalf by the Station Master is in charge of the operations, and unless the block section into
which the shunting is to take place is clear of an approaching train.
2.12
Obstruction out side the first stop signal at a class `B’ station on single line: The
line outside the first stop signal shall not be obstructed unless the line has been blocked back.
3.
3.1
Automatic Block system: [GR 9]
Essentials of Automatic Block System on double line: [GR 9.01]
Where trains on a double line section are worked on Automatic Block System:
3.1.1 The line shall be provided with continuous track circuiting or axle counters;
3.1.2 The line between two adjacent Block Stations may , when required, be divided into a
series of Automatic Block Signalling sections each of which is the portion of the running line
between two consecutive stop signals, and the entry into each of which is governed by a stop
signal, and
3.1.3 The track circuits or axle counters shall so control the stop signal governing the entry
into an automatic block Signalling section that:
(i)
The signal shall not assume an Òff’ aspect unless the line is clear not only up to the
next stop signal in advance but also for an adequate distance beyond it, which unless
otherwise directed by approved special instructions, shall be not less than 120 metres,
and
(ii)
The signal is automatically placed to Òn’ as soon as it is passed by the train.
3.2
Passing an Automatic Block signal at Òn’ on double line section: [GR 9.02]
Whenever a Loco Pilot finds an Automatic signal Òn’, he shall stop near the foot of signal and
wait for one minute in the day and two minutes in the night. If the signal does not assume Òff’
aspect during this waiting period, he shall give a prescribed code of whistle and exchange
63
signals with the Guard and then proceed ahead, as far as the line is clear, towards the next signal
in advance exercising great caution so as to stop short of any obstruction.
3.3
Essentials of Automatic Block System on single line: [GR 9.03]
Where trains on a single line are worked on Automatic Block System:
3.3.1 The line shall be provided with continuous track circuiting or axle counters,
3.3.2 The direction of traffic shall be established only after Line Clear has been obtained from
the block station in advance.
3.3.3 A train shall be started from one Block Station to another only after the direction of
traffic has been established.
3.3.4 It shall not be possible to obtain line clear unless the line is clear, at the Block Station
from which Line Clear is obtained, not only up to the first Stop Signal but also for an adequate
distance beyond it, which unless otherwise directed by approved instructions, shall be not less
than 180 metres.
3.3.5 The line between two adjacent Block Stations may, where required, be divided into two
or more of Automatic Block Signalling sections by provision of Stop signals.
3.3.6 After the direction of traffic has been established movement of train into, through and
out of each Automatic Block Signalling section shall be controlled by the concerned Automatic
Stop signal and the said Automatic Stop signal shall not assume Òff’ position unless the line is
clear up to the next Automatic Stop signal:
Provided further that where the next Stop Signal is a manual Stop signal, the line is clear for an
adequate distance beyond it, which unless otherwise directed by approved instructions, shall be
not less than 180 metres and
3.3.7
All stop signals against the direction of traffic shall be at ‘On’.
3.4
Minimum equipment of fixed signals in Automatic Block territory on single line:
[GR 9.04] The minimum equipment of fixed signals to be provided for each direction shall be as
follows:
3.4.1
3.4.2
Manual Stop signals at a station:
(i) A Home,
(ii) A Starter.
An automatic stop signal in rear of the Home signal of the station.
Note: Under approved special instructions, the Automatic Stop signal may be dispensed with.
3.5
Additional fixed signals in Automatic Block territory on single line: [GR 9.05]
3.5.1 Besides the minimum equipment prescribed in paragraph 3.4.1 above, one or more
additional Automatic stop signals, as are considered necessary, in between Block stations, may
be provided.
3.5.2 In addition, such other fixed signals as may be necessary for the safe working of trains
may be provided.
64
3.6
Conditions for taking Òff’ Manual stop signals in Automatic Block territory on
single line: [GR 9.06]
3.6.1 Home signal: when a train is approaching a Home signal, otherwise than a terminal
station, the signal shall not be taken Òff’ unless the line is clear not only upto the Starter but
also for an adequate distance beyond it.
3.6.2 Last stop signal: The Last Stop signal shall not be taken Òff’ for a train unless the
direction of traffic has been established and the line is clear upto the next Automatic Stop
signal, or when the next stop signal is a manual stop signal, for an adequate distance beyond it.
3.6.3 The adequate distance as mentioned above shall never be less than 180 metres and 120
metres in case of two aspect signalling and multiple aspect signalling sections respectively
unless otherwise directed by approved special instructions. A sand hump of approved design or
subject to the sanction of the Commissioner of Railway Safety, a derailing switch shall be
deemed to be an efficient substitute for the adequate distance.
3.7
Person in charge of working of trains in Automatic Block system on single line:
[GR 9.08]
3.7.1 Except where Centralised Traffic Control is in operation, the Station Master shall be
responsible for the working of trains at and between stations.
3.7.2 On a section where Centralised Traffic Control is in operation, the Centralised Traffic
Control Operator shall be responsible for the working of trains on the entire section except when
the station has been handed over to the Station Master, when he shall be responsible for the
station and between the stations.
3.7.3 On a section where Centralised Traffic Control is in operation, the working of trains at a
station or part of a station may be taken over by or handed over to the Station Master during
emergency or as prescribed by special instructions. When such emergency control is transferred,
the Station Master shall be the person in charge of working trains at the station or part of the
station and the station shall be worked accordingly.
3.8
Passing Automatic Signal at Òn’ on single line section: [GR 9.07] Whenever a Loco
Pilot finds an Automatic signal Òn’, he shall stop near the foot of signal and wait for one
minute in the day and two minutes in the night. If the signal does not assume Òff’ aspect during
this waiting period, he shall contact the Station Master of the next station or the Centralised
Traffic control Operator (CTC Operator) on a telephone provided near the signal and seek his
advise. If the Station Master or the CTC Operator, having ascertained clearance of the track
ahead, permits him to move ahead, the Loco Pilot shall move to the next signal observing
extreme caution and in case of visibility being poor due to curvature, rain dust storm or fog, he
shall move at an speed of not more than 8 kilometres per hour, even if the next signal is found
Òff’. The Loco Pilot shall act upon the aspect of next signal only after he has reached that
signal.
When no telephone is provided near the signal or it is not functioning the Loco Pilot shall
whistle on prescribed code and exchange signals with Guard. The Guard shall show a stop signal
towards the rear to warn the approaching train. In case there is no Assistant Loco Pilot with the
Loco Pilot, the Loco Pilot may seek assistance of the Guard by giving prescribed code of
whistle. In that case the Guard shall accompany Loco Pilot on the engine cab in keeping sharp
look out.
65
3.9
Passing a Gate stop signal at Òn’ in Automatic signalling territory: [GR.9.15]
3.9.1 If À’ marker is illuminated: The Loco Pilot shall observe the procedure for passing an
Automatic signal at Òn’ in double line section or single line section as described under
paragraph 3.2 & 3.8 respectively of the same chapter of this book.
3.9.2 If À’ marker is not illuminated: The Loco Pilot shall sound the prescribed code of
whistle to warn gateman and bring his train to stop at the foot of the signal., wait for one minute
during day and two minutes during night and if the signal is not taken Òff’, he shall proceed
with caution upto the level crossing and proceed further passing the level crossing gate if the
Gate man is present and exhibiting the hand signal. If the gateman is not available or is available
but not exhibiting the hand signal, the Loco Pilot shall stop his train in rear of the level crossing
and proceed after ascertaining that the gate is closed against road traffic and on getting hand
signal from the gateman. In absence of the Gateman he shall get the hand signal displayed by the
Assistant Loco Pilot, shall sound the prescribed whistle code and cautiously proceed upto next
signal.
4
Following train system:
4.1
Essentials of the Following Train System: [GR 10.01]
4.1.1 Where trains are worked on the Following Train system, they may be despatched from
one station to the next, following each other in succession in the same direction on the same line
in such a manner and at such interval of time as may be prescribed by special instructions.
4.1.2 Trains shall not be worked on Following Train system unless the Station Master of the
block station in advance has exchanged messages regarding his readiness to receive the trains
and has, in addition, given his assurance that no train will be allowed to leave his station for the
station from which the following trains are to be despatched, until the latter have all arrived his
station and until he as received permission to despatch trains in the opposite direction.
i)
ii)
Report to the commissioner of railway Safety: [GR 10.02] When the Following Train
System is introduced on any portion of a railway under Rule 7.01of GR, a report shall
be sent the Commissioner of Railway Safety.
Conditions to be observed in working Trains on the following train System:
[GR10.03] When the Following Train system is adopted, the following conditions shall
be observed, namely:
a) No train shall start until the Loco Pilot has been given written authority to proceed
in the form prescribed for the purpose and a written acknowledgment there of has
been obtained from him , the train being stopped for the purpose, if not booked to
stop,
b) The authority to stop shall state the station at which the train is next to stop, the
speed at which it is to run and actual time of departure of the preceding train,
c) The Loco Pilot and Guard of each preceding train shall have been informed of the
fact that a train will follow, and of the probable period which will elapse before the
following train shall start,
d) A train shall not follow another from a station unless there has elapsed since the
departure of previous train, an interval of not less than 15 minutes, or such shorter
interval as may be fixed by special instructions.
e) All the trains following the first train shall be timed to run at the same speed and
such interval as maybe fixed by special instructions,
66
f) The actual time of departure of each train shall at once be intimated to the block
station in advance and the actual time of arrival of each train shall at once be
intimated to the block station in rear, and
g) The number of following trains running at the same time between any two Block
stations shall not be more than one for each 5 kilometres of station interval; and
unless permitted by special instructions, shall never exceed four, whatever may be
length of the station interval.
5
Pilot Guard System:
5.1
Essentials of the Pilot Guard System: [GR 11.01] Where trains are worked on the
Pilot Guard System:
5.1.1 A railway servant ( herein after called a Pilot Guard) shall be specially deputed to pilot
trains; and
5.1.2 No train shall leave a station except under the personal authority of the Pilot Guard.
5.2
Conditions to be observed for following trains on the Pilot Guard system:
[GR11.02] Trains shall not follow one another in the same direction between stations, unless:
5.2.1 The Loco Pilot has been properly warned of the preceding train and of the place at
which it will next stop;
5.2.2 All the trains are timed to run at the same speed, and such speed shall not exceed 25
Kilometres an hour except under special instructions; and
5.2.3 An interval of fifteen minutes has elapsed since the departure of the preceding train.
5.3
Pilot Guard’s dress or badge: [GR 11.03] The pilot Guard shall be distinguished by
red dress or badge.
5.4
Pilot Guard to accompany every train or give authority to proceed: [GR 11.04]
5.4.1 No train shall be started from a station unless the Loco Pilot sees that it is accompanied
by, or that the authority to proceed is given personally by the Plot Guard wearing the dress or
badge prescribed in GR 11.03.
5.4.2 The pilot Guard shall accompany every train: “Provided that when it is necessary to start
two or more trains from one end of the section before a train has to be started from the other end,
the Pilot Guard shall accompany only the last of such trains.”
5.4.3 When accompanying a train, the pilot Guard shall ride on the footplate of the engine.
5.5
Pilot Guard’s Tickets: [GR 11.05]
5.5.1 When the Pilot Guard does not accompany a train, he shall deliver to the Guard (or, if
there be no Guard, to the Loco Pilot) a Pilot Guard’s ticket on a printed form properly filled up
and signed in ink, as the authority to proceed.
5.5.2 Every such ticket shall apply only to the single journey to the station named on it.
5.5.3 If the train is in charge of a Guard, he shall, before the train is started, deliver the ticket
to the Station Master who shall at once cancel it.
67
5.6
Protection of train on Pilot Guard system: [GR 11.06] In the event of a train, which is
followed by another train, stopping on the line between stations, the Guard and the Loco Pilot
shall take action to protect the train in accordance with the provisions of General Rule 10.09.
6.
Train Staff and Ticket System:
6.1
Essentials of the Train Staff and Ticket System: [GR 12.01] Where trains are worked
between two stations on Train Staff and Ticket System:
6.1.1 A single Train – staff shall be kept at one of such stations, and
6.1.2 No train shall start from either of such stations to the other unless the said Train Staff is
at the station from which the train starts and has either been handed to or shown to the Loco
Pilot by the Station Master when giving such permission.
6.2
System where applicable: [GR 12.02] Trains may be worked on the Train Staff and
Ticket system only when the line is single and only between such stations as have been declared
by special instructions to be Train staff Stations.
6.3
Conditions to be observed for following train on the Train Staff and Ticket System:
[GR 12.03] Trains shall not follow one another in the same direction between Train Staff
stations, unless:
6.3.1 The Loco Pilot has been properly warned of the time of departure of the preceding train
and of the place at which it will next stop;
6.3.2 All the trains are timed to run at the same speed, and such speed shall not exceed 25
kilometres an hour except under special instructions ; and
6.3.3 An interval of fifteen minutes has elapsed since the departure of the preceding train.
6.4
Loco Pilot to have Train Staff or Train Staff Ticket: [GR 12.04] No train shall be
started from a station unless the Loco Pilot has in his possession to be carried with him on
journey, either the Train Staff or Train Staff Ticket, for the section of the line over which the
train is about to travel.
6.5
Train Staff or Train Staff Ticket to be delivered to: The Train Staff Ticket shall be
delivered to the Loco Pilot by Station Master or by some railway staff servant appointed in his
behalf by special instructions.
6.6
Train Staff or Train Staff Ticket to be delivered when: Train Staff or Train Staff
Ticket shall be delivered to the Loco Pilot when: [GR 12.06]
6.6.1 When no other train is intended to follow before the Train Staff is required for a train in
opposite direction, then subject to the provisions of the rule given under paragraph 6.6.3 of this
chapter as below, the Train staff shall be delivered to the Loco Pilot.
6.6.2 When other trains are intended to follow before the Train Staff can be returned, then,
subject to the provisions of following rule given under paragraph 6.6.3 of this chapter, a Train
staff ticket indicating that the Train Staff is following, shall be delivered to the Loco Pilot of
each train except the last; and the Train Staff shall be delivered to the Loco Pilot of the last train.
68
6.6.3 A train is assisted by second engine in rear, a Train Staff Ticket shall be delivered to the
Loco Pilot of the front engine and the Train Staff shall be delivered to the Loco Pilot of the rear
engine:
Provided that if both the engines attached to the train travel over the entire length of line to
which Train staff applies, and the train is to be followed by the trains, a Train Staff Ticket
shall be delivered to the Loco Pilot of each of the engines attached to the first mentioned train.
6.6.4 When a train is assisted by a second engine in front, the Train Staff or Train Staff
Ticket, as the case may be, shall be delivered to the Loco Pilot of leading engine.
6.6.5 When a material train has to stop between stations, the Train Staff shall be delivered to
the Loco Pilot.
6.7
The Train Staff or Train Staff Ticket shall not be delivered to the Loco Pilot of any train
until the train is ready to start.
6.8
The Loco Pilot shall not accept a Train Staff Ticket unless he sees the train staff at the
same time in possession of the person who delivers the Train Staff to him.
6.9
Train Staff to be kept on engine: When the Train Staff is delivered to the Loco Pilot of
a train, he shall place it in a conspicuous place provided for the purpose on the engine.
6.10
Trains not to be started until Train Staff returned: When the Train Staff has been
taken away from a station by the Loco Pilot of a train, no other train shall be started from that
station to follow the first mentioned train until the Train Staff has been returned to the station.
6.11
Train Staff or Train Staff Ticket to be given up and Ticket to be cancelled on
arrival of train: [GR 12.09]
6.11.1 Upon the arrival of a train at the station to which the Train Staff or a Train Staff Ticket
extends, the Loco Pilot shall immediately give the Train Staff or Train Staff Ticket to the Station
Master, or to some railway servant appointed by special instructions to receive it.
6.11.2 The person to whom any such Train Staff Ticket is to be delivered shall immediately
cancel the same.
6.12
Procedure when engine is disabled on the Train Staff and Ticket system:[GR 12.10]
6.12.1 If an engine, which carried the Train Staff, breaks down between two stations, the
Assistant Loco Pilot shall take the train staff to the staff station in the direction where assistance
can best be obtained, in order that the Train Staff may be available at the station for delivery to
the Loco Pilot of assisting engine.
6.12.2 If an engine which carries a Train Staff Ticket breaks down between two stations,
assistance shall ordinarily be obtained only from the station at which the Train Staff has been
left but if assistance can more readily be obtained from another station in the opposite direction,
immediate steps shall be taken to have the Train Staff transferred to the other end of the section.
6.12.3 Whenever an engine has broken down between two stations the assistant Loco Pilot
shall accompany the assisting engine to the spot.
6.13
Train staff Tickets, how kept: Train Staff Tickets shall be kept in a ticket box provided
for the purpose and fastened by an inside spring, the key to open the box being the Train Staff to
69
which the tickets apply. Train Staff when at a station shall not be left in the box but shall be kept
by the Station Master in safe custody.
6.14
Distinguishing marks on Train staff Tickets and boxes:
6.14.1 Each train staff shall have shown upon it the name of the Train staff station at each end
of the portion of line to which it applies.
6.14.2 The Train staff and Train staff Tickets and boxes for the different portion of the line
shall be distinguished by different colours.
6.14.3 ÙP’ and Down Train staff Tickets shall also have distinguishing marks.
6.15
Form of Train staff Ticket: Every Train staff Ticket shall be in following form:
The Loco Pilot shall not accept this ticket unless he sees the Train staff for the portion of line,
which he is about to enter. This ticket shall be given up by the Loco Pilot, immediately on
arrival, to the Station Master or other person authorised to receive it, and such person shall
immediately cancel it.
6.16
Record of Train staff Tickets issued: The Station Master shall keep a record in a book
of each Train staff Tickets issued, showing the number of each ticket and the particular train for
which it was issued. A sample of back of the Ticket is given below.
(Back of Ticket)
Ticket No.-----------------------Railway
TRAIN – STAFF TICKET
(UP or DOWN)
Train No.--------------Time ----------Hours------------Minutes
From---------------------------------To--------------------------------To Loco Pilot and Guard,
You are authorised to proceed from--------------------------station
To ----------------------station and the Train staff will follow.
Train No.------------------in front left------------hours----------minutes
Signed---------------------Station Master at----------(Station Stamp)
Date:-------------------------6.17
Obstruction outside the Home Signal: The line out side the Home signal shall not be
obstructed unless the Train Staff of the portion on the line to be obstructed is at that station.
7.
One train Only System:
7.1
Use of One Train Only System: [GR 13.01] Trains may be worked on the One Train
Only System, only on short terminal branches on the single line.
70
7.2
Essentials of the One Train Only System: [GR 13.02] Where the trains are worked on
the One Train Only System, only one train shall be on the section on which this system is in
force, at one and the same time.
7.3
Authority to enter the section: [GR 13.03] A Loco Pilot shall not take his train into the
section unless he is in possession of the authority to proceed as prescribed by special
instructions.
*****
71
Chapter- III Self Assessment
1
2
3
4
5
In ‘A’ marker on manual stop signal, when
illuminated indicates that:
a) The signal is non functional
b) The signal can be passed at ‘On’ aspect
at full speed
c) The rules for Auto Block section shall
be followed*
d) The signal shall be treated as
Automatic Block signal only when it is
‘On’
On a ‘B’ class station on double line section,
line clear can be granted when:
a) The shunting is being performed with
the station section
b) Only after shunting is stopped on the
line on which the train is scheduled to
be received
c) Both a) and b) are correct
d) Only a) is correct*
In normal course only two of the following
systems can be used, for any system other
than which, Railway Board’s approval shall
be required:
a) Absolute Block system & Train
following system
b) Train following system & Automatic
Block system
c) Absolute Block system & Automatic
Block system*
d) Automatic Block system & One train
only system
Automatic Block signal shall assume ‘Off’
aspect as soon as:
a) The track circuit ahead of signal is
clear
b) Not only the track circuits ahead of the
signal but the overlap track circuit
beyond next signal is also clear *
c) All track circuits ahead of signal &
next signals are clear
d) None of the above
6
Under Pilot Guard system the normal permitted
speed of the train shall be:
a) 25 kmph*
b) 20 kmph
c) 15 kmph
d) 50 kmph
7 Under Pilot Guard system the Pilot Guard shall
be distinguished by:
a) Navy blue dress or badge
b) White dress or badge
c) Orange dress or badge
d) Red dress or badge*
8 At ‘C’ class station on double line section, line
clear can be granted only when:
a) Preceding has left the station
b) The preceding train is still moving having
cleared 400Mts beyond the home signal
c) The preceding train is still moving having
cleared 400Mts beyond the home signal or
has left the station & the Home signal has
been put to ‘On’*
d) The train has passed home signal & the
signal has been replaced to ‘On’
9 On single line section provided with Automatic
Block signalling, direction of traffic shall be
established only when:
a) Line clear has been obtained from station
in advance
b) All trains in the direction opposite have
cleared complete Automatic Block section
between the two stations
10 In Automatic Block signalling section the ‘A’
marker provided on gate signal is illuminated
when:
a) The Gate signal is working as an
Automatic Block signal
b) The Gate may not be Closed & locked
Under Absolute block system of working on an ‘A’ class station on double line section, line clear can
be granted only when:
a) All shunting at the station has been stopped
b) Line on which train is scheduled to be received is clear upto Starter signal
d) Only b) is correct*
72
1.
2.
3.
4.
5.
6.
There are nine systems of operating on Indian Railways as per GR. Chapter-VII. True/False*
In Automatic Block Signalling section the normal aspect of the signal in ‘Off’. True*/False
The control of the station can not be transferred by CTC controller to Station Master. True/False*
Any of the operating system can be provided on Indian Railway without reporting to Commissioner of
Railway Safety. True/False*
Under train staff & ticket system of working the Loco Pilot shall accept the ticket when delivered by
Station Master. True/False*
While using Following Train System a train shall not follow another from a station unless a fixed
prescribed period has lapsed after the departure of previous train. The normal period is not less than 15
minutes. True*/False
1.
2.
3.
4.
Discuss Essentials of Absolute Block system of working including minimum equipment to be provided
at the station on double line section.
Discuss essentials of Automatic Block system of working including minimum equipment to be
provided at the station on single line section.
Discuss advantages and disadvantages of Absolute Block system compared to Automatic Block
Signalling.
Write short notes on:
a)
One Train Only System
b)
Pilot Guard System
*****
73
CHAPTER –IV
INSTALLATION & BRINGING IN USE, OF SIGNALLING SYSTEMS
1.
Construction Organisation: A vibrant organisation is continuously in progress mode.
So is Indian Railways. Progress is usually associated with construction activities. Rightly so
each Zonal railway has dedicated construction organisation.
The organisation is headed by Chief Administrative Officer (CAO) Construction, who is
responsible to General Manager of the railway concerned. The CAO is assisted by Chief
Engineer, Chief Electrical engineer, Chief Signal & Telecommunication Engineer and
FA&CAO, with suitable supporting paraphernalia supporting them. All other supporting
departments like Personal, and Operating etc are also under CAO, at levels suitable to bear
responsibilities for discharge of their duties depending upon volume of work and to make the
organisation compact and independent. Some times the duties of one or more departments are
shared with open line when the work load does not warrant the requirement of dedicated officers
and staff. Some times Construction organisations are headed by General Manager also.
Central Organisation for Railway Electrification (CORE) is another organisation headed by
General Manager, is dedicated to Railway Electrification all over Indian Railways. With the
electrification, the signalling and telecommunication installations have to go for radical system
changes. The affect of electrification on signalling and telecommunication has been discussed in
ensuing chapter-VI of this book. CORE is a major organisation undertaking provision of AC
traction and changes to signal and telecommunication system.
Apart from the dedicated construction organisation under CAO, some low value construction
works are also taken up by open line to meet their local and small needs by posting officers
against work charge posts.
Some high value capital intensive works are outsourced to IRCON, Rail Vikas Nigam Ltd.
(RVNL), Indian Railway Project Management Unit (IRPMU) and other Public Sector Units
(PSUs). The work of freight corridor has been taken up by Dedicated Freight Corridor
Corporation.
The Chief Commissioner of Railway Safety is posted under Ministry of Surface Transport,
Central Government of India. There are Zonal Commissioners of Railway Safety who are
responsible for one or more Zonal railways. It is prescribed in the General Rule 3.26 that `Fixed
signal shall not be brought into use until they haven passed by Commissioner of Railway Safety
as being sufficient to secure the safe working of trains,’ accordingly concerned Commissioner of
Railway Safety is required to be approached for requesting permission for opening of a railway
or a portion thereof, for public use.
2
Finances for construction organisation: Pursuant upon recommendations of Acworth
Committee (1920-1921), railway finances were separated in 1924 from general finances
primarily to secure stability for civil estimates by providing for an assured contribution from
74
railway revenues and also to introduce flexibility in the administration of railway finance.
Review of this arrangement kept on getting postponed on one or the other reason till a new
convention 1949 was adopted with effect from the 1st April, 1950, after independence.
2.1
Revenue receipts: Major portion of revenue of the railway is received from the
transport of goods, passengers which includes earnings from defence warrants, vouchers, other
rail travel such as MPs etc, parcels, animals and other merchandise. Remaining is received from
catering and advertisement fees etc.
2.2
Revenue expenditure: The public money can be spent in two ways only. It may be
either `charged Expenditure’ or `Voted Expenditure’. The Charged expenditure is done against
Judicial awards and any other expenditure is `Voted Expenditure’. For expenditure against
judicial awards parliament’s sanction is not required. The parliament represents public, as such
for any expenditure other than Charged expenditure, sanction of parliament is required, which is
voted by parliament. The expenditure is also approved by president.
The sanction of parliament’s or the President is requested in the form of `Demands for Grants’.
The approval by the parliament is granted in the form of `Grants’ after the same has been voted,
while the approval by the President is granted in the form of Àppropriations’ [SEM 19884.1.3]. The revenue expenditure is requested through demand numbers 1 to 15.
Demand number 1- is for Railway Board, 2 – for Miscellaneous expenditure(General), Railway
Recruitment Board & survey, 3- is for general superintendence, services & administration, 4- is
for Repairs and maintenance (R&M) of Permanent way & works including Ballast, 5- is for
R&M of Motive Power, 6- is for R&M of C&W, 7- is for R&M of plant & equipment, 8- is for
Operating expenses, rolling stock & equipment, 9 & 10- are for Operating expenses, 11 – is for
Staff welfare and amenities, 12- is for Miscellaneous expenses, 13- is for P.F., pension & other
retirement benefits, 14- is for Appropriation to funds and 15- is for Dividend to general
revenue.
The main expenditure from the revenue receipts is on working expenses of railways which
includes salaries of employees, all expenditure on fuel, operation, repairs & maintenance of
assets, locomotives, coaches, S&T equipment etc;
2.3
Capital source of fund and expenditure: The expenditure on railways by Central
Government is financed through a) loans raised specifically for railway purpose; b) Out of
revenue surplus of railway which is at the disposal of Government, and c) Contributed by Indian
states and District Boards etc.
Capital expenditure is done out of grant for demand number 16 under the heading Àsset
Acquisition, Construction & Replacement’. The demand for grants number 16 is further grouped
under five subheads:
2.3.1 Capital fund (Cap): The amount granted against this fund is financed by Central
Government only when rate of return is 14% or more. Railway is required to pay interest to
Central Government at a specified rate.
75
2.3.2 Capital fund (CF): The expenditure against this fund is done out of surplus railway’s
own earnings.
2.3.3 Depreciation Reserve fund (DRF): Allocation to Depreciation Reserve Fund, started
from 1st April, 1924 for renewals of the assets which have time bound normal life. The amount
of this fund remains in deposit with the Central government;
2.3.4 Development fund (DF) -1: The Development Fund started with effect from 1st April,
1946, with the name of Railway Betterment Fund, modified to be named as Development Fund
on 1st April, 1950, and to be used for Passenger Amenities only, which included amenities for all
users of railway transport, labour welfare works such as class III staff quarters and unremunerative project for improvement of operational efficiency. It is further regrouped as:
i)
ii)
iii)
iv)
DF-1: Fund for passengers and other railway users amenities,
DF-2: Fund for staff welfare,
DF-3: Fund for Operating improvement,
DF-4: Fund for safety works.
2.3.5
Open Line Works (Revenue): Other open line works are carried out under this head.
2.4
Safety fund (SF) and Special Railway safety Fund (SRSF) have now been merged with
DF-4 & DRF respectively, with effect from 1st April 2008.
2.5
Construction organisation is broadly required to carry out works generated under Capital
supplemented by Development fund, Deprecation Reserve Fund and open line revenue works.
2.6
All new works such as laying of new lines or provision of Electric traction is carried out
financed by Capital. The work is undertaken only when it is found to be remunerative with a
predetermined Rate of Return (RoR). The present RoR is 14% to justify the work. While
planning works under Capital it often implies to incorporate certain development or renewal
work to save cost of duplication and as such these works are also clubbed and funded from these
funds as well.
3.
Execution of works: Indian Railways absorbed huge work force which was working as
casual labour for long periods. Railway also decided to reduce its work force gradually. With
this depleting work force available for construction works, railway had to resort to contractual
system for execution of works.
The work may be of execution on running lines or New Lines and Electrification.
In both the cases safety of the travelling public is ensured by the rules laid down in:
[SEM 1988- 9.1.1]
i)
The Indian Railway Act,
ii)
The General Rules for all Open Line Railways,
iii)
The Rules for Opening of a Railway or a section of Railway for public carriage of
passengers, and
iv)
Indian Railway Schedule of Dimensions.
76
These rules provide for legal authorisation that shall be obtained for any work which affects the
running line, before the work is started or brought into use and before a new section of a line
opened for public traffic. {SEM 1988-9.1.2].
3.1
Tenders: besides many meanings of Tender’ in the Dictionary, one is “`to make an
offer to carry out work”. So a tender is the offer for service by a tenderer for carrying out the
work at the rates agreed with him. Tenders are invited through advertisement in news papers,
directly advising working contractors of the organisation, and web site of the organisation, from
those interested in execution of the work, out of which one tenderer, which is most economical
offer from adequately experienced and financially sound qualifying other eligibility conditions is
chosen.
To begin with, the work content is decided. The work could be got executed through contractor
on “Turn Key Basis” where all elements such as supply of all material required for execution of
entire work, designing ,planning etc of work content are included in the contract. In other case a
part of the material supply and other elements of work such as planning & designing is retained
by railway with itself and balance is included in the contract.
3.1.1 Cost of work: According to the scope of work the entire work content is divided into
units of workable activities. The rates of each activity are calculated, this process of working out
rates of each activity is called Rate Analysis. Rate Analysis has three basic elements, i) Working
out cost of material: The latest cost of all material scheduled to be supplied and used by
contractor for the activity is worked out. This shall not include the cost of material scheduled to
be supplied by Railway if any, ii) Labour cost: Cost of all labour is worked out; iii) Contractors
profit over material and labour cost combined together @ 10% to which overheads and taxes are
added: Taxes shall be worked out on material part only while overheads such as supervision etc
is worked out on material and labour combined. The total of Material and Labour cost,
Overheads and contractor’s profit shall become the cost of each activity independently for one
unit of work. This is called Ùnit Rate’ of the activity. The unit rate becomes SOR of the year in
which the same is adopted.
The quantities against activities, which are to be operated in the given tender are filled. The cost
of each such activity is worked out by multiplying the quantity of the activity & unit rate and the
cost of all activities added together shall be the cost of total work or cost of contract. This
document containing all activities with associated rates is called `Schedule of Rates’ (SOR) and
also some times `Bill of Quantities’ (BOQ).
In certain cases when an activity which is not available in the SOR, the activity required to be
operated in a given contract, the cost of the activity is either prepared through rate analysis or
from the rates of latest accepted contract. Such items of activity are called Non Schedule items.
It is pertinent to note that the cost of each activity has to be realistic as this cost shall become the
basis for deciding cost of the work as offered by the tenderer being reasonable, high or low. It
shall be seen later that any exaggeration in framing the cost of activities shall result in paying
higher cost for the work, and conservative calculation shall lead to a situation where it shall
appear that the cost offered by the tenderer is high to which it shall be difficult to accept. The
77
consent of associated finance i.e. concurrence, shall be obtained for rate analysis of each such
activity independently as well as for complete schedule of rates. Rate analysis shall be approved
by an authority competent to do so in conformity to Schedule of Powers. A sample rate analysis
is given as below:
Rate analysis for preparation of signal foundation in station area.
Description of the work: Digging earth, casting foundation as per drawing attached along with
foundation bolts and plastering surface with sand cement and stone chips (25MM) of 1: 3: 6, ratio with
fine finish, quenching the foundation for six days minimum, ramming the earth around the foundation
clearing and cleaning the area to its original shape. = 20 Numbers
Specifications:
Size of the foundation ……Cu Mts
Ratio of Sand: Cement: Stone chips.
Size of stone chips = ….
SN
Material
Quantity
…Cum
Rate in
Rs.
…..
Cost in
Rs.
Rate * qty
1
Sand coarse
2.
Cement
…Cum
…..
Rate * qty
3.
Stone chips
…Cum
…..
Rate * qty
4
Foundation Bolts with two
nuts and washers
1 set
…..
Rate * qty
5
Pipe for cable entry
One piece
1
Meson
TOTAL COST
VAT @ .....%
TOTAL COST OF
MATERIAL
one
…..
2
Labour
4
Supervisor 10%
TOTAL COST OF
LABOUR
One
….
A
B
C
Overhead charges @ 15% of
A+B+C
E
Cost of work = A+B+C+D
F
Contactor’s profit
Unit cost of Work
Approved by ………
…..
D
10%
Vetted by ………
78
Reference of rate
Builder’s book for the
month of ……
month of ……
month of ……
Budgetary
quotation
number…….dated….
from ……attached as
Annexure-1
Lump
Sum
….
…..
…..
Rate * 1
Rate * 4
Rates issued by labour
commissioner dated…
…
Rate * 1x
10%
….
X
X*10%
X /20 =Y
Prepared by………
3.1.2 Schedule of Rates SOR: In organisations where the work is of repetitive nature,
preparation of SOR is done once. The rates for all possible activities are prepared once by a
committee consisting of one executive member and one member from associated finance. The
fiancé concurrence is obtained for all such rates as worked out by the committee, which is
sanctioned by the Chief Signal & Telecommunication Engineer in case of SOR for S&T
department, to become SOR of the year in which the same is adopted for implementation. A
sample schedule of rates is shown as follows:
SN Schedule of work
Unit Rate in Rs.
In
In
figures
words
Job Y
….
1
Digging earth, casting foundation as per drawing number
…… attached, along with foundation bolts and plastering
surface of the foundation with sand cement of 1: 3 ratio to
fine finish, quenching the foundation for minimum six days,
ramming the earth around the foundation, clearing and
cleaning the area to its original condition.
2.
3.
4.
3.1.3 Items not covered in SOR: It is possible that some items are not covered in SOR.
Under such a situation the job content is identified and rates analysed and concurred by associate
finance. Such items are known as Non- Scheduled items as these are not taken out of SOR but
are prepared for the specific contract.
3.1.4 Inviting tenders: Once the schedule of rates is ready including SOR and Non SOR
items, the quantities are filled in for the work proposed, for each activity to prepare schedule of
quantities and rates for the work on the format as shown below bringing out total cost of the
proposed work:
SN Schedule of work
Unit Quantity Rate in Rs.
Cost in
In figures In words Rs.
Y
….
Y*20
1
Digging earth, casting foundation Job 20
as per drawing number ……
attached, along with foundation
bolts and plastering surface of the
foundation with sand cement of
1: 3 ratio to fine finish, quenching
the foundation for minimum six
days, ramming the earth around
the foundation, clearing and
cleaning the area to its original
condition.
2
-3
Non Schedule item of work
3.1 - TOTAL COST OF WORK Rs.
79
This statement, after taking approval of the authority competent to accept the tender shall be putup for finance concurrence.
After the finance concurrence is received, a Tender Notice, giving adequate information of the
work content, total cost of work, earnest money amount, which is a given % of the cost of work
decided from time to time, to be deposited giving accurate information about the form in which
the amount is to be deposited and the name in favour of whom (The associated finance officer at
appropriate level) the instrument shall be prepared, the time and date by which the tenders shall
be accepted indicating place or person where the tenders shall be received, shall be i) circulated
through daily Hindi and English news papers having good circulation in the area of work and the
area where the tenders are to be deposited; ii) pasted on the notice board in the office; iii) placed
on the web site of the organisation, giving not less than 30 day’s time for receipt of the tenders,
except under special circumstances where time may be reduced to not less than 15 days, under
approval of competent authority. The tenders invited with such reduced time are called as `Short
Tenders’.
3.1.5 Tender documents: The Schedule of Rates shall be accompanied with i) Instructions to
the tenderer for filling in the tender documents, ii) Specifications and drawings for execution of
the work iii) Specifications for the materials to be supplied and used by the contractor and
agency for inspection, iv) Special conditions of the contract including Arbitration clause, v)
General conditions of contract issued by the railway in the zone of which the work shall be
executed.
3.1.6 Opening of tenders: Usually a `Tender Box’ closed and sealed with an opening in the
cover of the box, is kept in the office of the executive at an appropriate safe place, easily
accessible to bidders. With information of the name of work and tender number displayed on the
box indicating last date and time of receipt of the tenders.
There has to be a gap between closing time of receipt of the tenders and the time of opening of
tenders. The box shall be closed and sealed immediately on lapse of the scheduled time of
receipt of the tenders and opened by one representative of the executive not below the rank of
Assistant Signal & Telecommunication Engineer jointly with associated finance representative
not below in rank of Section Officer. All tenders shall be stacked in one room, and opened
jointly by the two officers in presence of those tendereres or their representatives who may
chose to participate in opening of tenders, possessing adequate authority from the tenderer. The
cover/envelops containing the tender documents shall be numbered from 1 to the last, not
necessarily in any sequence and signed by both the officers having encircled the number put on
the envelope. Wherever signed both officers shall jointly sign, using only red ink pen for the
entire process of opening. Each signature shall be with date.
The covers/ envelops shall be opened one by one in the numbered sequence , tender documents
taken out and covering letter, each page of schedule of rates and any special remarks or the
conditions put on by the bidder shall be similarly marked with the same number as put-on the
cover/envelop. Each and every rate offered in figures and words including any special remarks
in offer letter as well as otherwise any where and any corrections or overwriting, shall be
encircled and signed. In case more than one correction or overwriting, each such correction and
overwriting shall be marked as 1, 2, 3 etc and finally totalled as … corrections. Each page of the
80
tender shall also be signed. The rates of each item of schedule of all the tenderers shall be
announced clearly and distinctly if even one representative of any tenderer is participating in the
opening process.
The basic idea of entire process of opening of the tenders is that i) it shall not be possible to
modify, alter or replace any part of tender document without being known, ii) rates of all the
tenderer are made open and known to other bidders, and iii) late & delayed tenders are
separated out.
3.1.7 Delayed tenders: The tenders received after the lapse of time of receipt of the tenders
but before opening of the tenders are ‘Delayed Tenders’.
3.1.8 Late tenders: The tenders received after the scheduled time of opening, are ‘Late
Tenders’.
Delayed as well as late, both types of tenders shall not be considered for award under normal
circumstances. However these shall be numbered last and marked conspicuously with red ink as
Delayed or Late tender.
These tenders may be considered if approved from Railway Board on recommendations of Head
of the Department in association with finance, under extreme circumstances such as nonavailability of bidders, under extreme emergency or heavy financial implications benefiting
railways.
3.1.9 Award of Contract: A tender becomes a contract once an agreement is signed between
Railway authority concerned and the tenderer. The procedure for award of tender and signing of
contract agreement is discussed in ensuring paragraphs.
3.1.10 Last Accepted Rates (LAR): The cost of work is required to be decided before inviting
tenders as the Ernest money to be called with tenders is based on the cost of work while at the
same time the cost of work is also the basis for deciding the reasonability of the cost tendered by
different tenderers.
The cost of work is calculated based on the Rate Analysis of all items of schedule at the time of
calling the tenders as discussed under preceding paragraph Ìnviting tenders’. However there
may be two situations i) Rate Analysis for all items might not have been required to be done
there being some items of schedule, the rates of which might have been analysed and accepted
for some earlier contract at that time, ii) time may have elapsed between inviting the tenders and
evaluating the same for reasonableness, and iii) some other contract bearing the same schedule
of quantities having been awarded in between inviting the tender in question and evaluation of
the reasonability of its cost. As such it becomes important to work out the cost of the contract
again some times just before opening of the tenders based on latest accepted rates and other
relevant information such as increase in rates of certain items scheduled to be supplied by the
contractor such as steel, cement etc. It is pertinent to note that the LAR shall be prepared before
opening of the bids to eliminate possibility of charge of any biases. The LAR so prepared shall
be got concurred by associated finance.
81
3.1.11 Briefing note: A note to brief the tender committee, containing statement of Last
accepted Rates duly concurred by finance, a tabulated comparative statement of the rates offered
for all items, by all the bidders, all special remarks or conditions as mentioned by the bidder and
any other matter effecting the nature of the offer, duly vetted by associate finance, along with all
tender documents, shall be put up to the tender committee by an officer one level below the level
of the tender committee member of the department of which the tender pertains. It shall be
specifically mentioned in the briefing note if there is any one of the Public Sector Unit (PSU)
amongst tenderer with a note that the PSU is entitled for purchase preference benefit. The
purchase preference benefit means that if the total cost of the work as offered by the PSU is
within 10% of the valid tenderer’s total cost of work, the PSU shall get priority over the other
lowest bidder i.e. PSU, shall be considered as lowest tenderer.
3.1.12 Tender Committee: Usually a standard tender committee is nominated by the General
Manager at different levels depending on the cost of work. The level of Tender committee is
however decided based on the cost offered by lowest valid bidder in case of two packet system
where the valid bidders are decided through credential bid before opening of the price bid.
However in one packet system, the level of Tender Committee shall be decided on the cost of
work offered by the lowest bidder. In case the Tender Committee finds that the lowest bidder
does not quality on credentials & he is declared to be invalid bidder on this ground or on
grounds of other eligibility criteria, the Tender Committee shall see if the cost of work offered
by the next valid bidder falls with in the range of consideration of the committee. In such a
situation it shall go ahead & draw tender committee minutes & recommendations. If the next
lowest valid bidder does not fall with in the consideration range of the Tender Committee it shall
not deal with the rates offered, but shall forward the complete case to next higher level Tender
Committee with minutes & recommendations bringing out facts, jointly signed by all Tender
Committee members.
An officer from Finance and an officer from the department for which the tenders are invited
shall essentially be the member of any tender committee. There may be more than two members
in the tender committee basically depending upon the cost of work and other reasons. The third
member shall be from a technical department other than the one for which the tenders are
invited.
The committee shall go through the briefing note and all documents, put-up to the committee. It
shall ensure that all documents required to be concurred or vetted by finance have been done so.
All tender documents submitted to the committee are intact and not tempered.
The tender not accompanied with the Ernest money shall be summarily rejected. For the works
costing more than Rs.10 lakhs, one of the major qualifying criteria is that the tenderer should
have completed at least one similar single work for a minimum value of 35% of
advertised tender value during preceding 5 years. The committee shall then evaluate the
credentials of the tenderers with reference to the conditions incorporated in the tender
documents and decide the tenderers qualifying the eligibility criteria. The tenderers having
qualified the eligibility criteria are the eligible tenderers. The committee shall then consider the
82
rates offered by the lowest, valid, eligible and technically acceptable tenderer only while
simultaneously comparing the rates offered by other bidders in the same tender.
The committee shall then see rates of all items through the comparative statement vis-à-vis the
LAR and examine each item of schedule for reasonability of rates. Following situations may
arise:
i)
Over all rates are within reasonable limits of acceptance but rates of some of the items
of schedule are high;
ii)
Over all rates are higher than acceptable limits and there is a scope of bringing down the
rates of some of the items of schedule, with which overall rates shall come down to
acceptable limits;
iii)
Over all rates are lower and considered to be unworkable i.e. it may not be possible to
execute the work by the bidder at the rates quoted by him.
Under first situation where Over all rates are within reasonable limits of acceptance but rates of
some of the items of schedule are high, the committee may recommend the acceptance of the
tender with rider that the rates which are high shall not be taken as LAR for future tenders. It
shall be kept in view that the rates quoted high are not very much disproportionate with respect
to other items of work.
In second situation the Lowest Eligible bidder shall be invited to negotiate the rates. Here it is
pertinent to note that i) The tender committee can deal with lowest eligible bidder only, ii)
discharge of tender because of high rates has two serious repercussions, first being that the work
shall get delayed and the second that in case of re-tendering the Tender Committee shall be
placed defensive if the rates offered by the lowest eligible bidder in the second tender turn out to
be higher than the first tender’s lowest rates. It is recommended that the tender committee
exhausts all possible channels of awarding the contract before recommending discharge of the
tender.
Under third situation, if the contract is awarded and contractor fails to complete the work
thereby the railway falling into the situation of processing award of another contract to get the
balance part of the work executed by another agency at the Risk and Cost of the failed
contractor. In this case too discharge of the tender, is fraught with the danger of similar situation
as in case of second one, as such in this case too it must be ensured that the rates are really
unworkable before recommending discharge.
Risk & cost contract: In case a contractor fails to carry out the awarded work within given
time, despite of best efforts of railway, the balance part of the work is required to be executed by
another contractor at the risk and cost of the failed contractor. In such a situation, the process of
award of contract for the balance part of the work (risk and cost contract) is same as a normal
contract. The risk and cost tender shall be under the same type and terms and conditions as that
of original tender for floating risk and cost tender. It shall be ensured that the contractor against
whom risk and cost tender is being floated is also be advised of the notice the risk and cost
tender against him. When the cost of balance work is higher because of higher rates, the
difference shall be realised from the failed contractor. For realisation of the difference cost, the
83
failed contractor shall be given notice to deposit the cost within given time. In case he fails to do
so, the money shall be realised by advising all Indian railways to withhold the amount due to be
paid by the failed contractor and release the extra amount, if any, after realising the amount due
to the railways, with in the preview of tender conditions.
The Tender Committee shall record its minutes of meeting, discussions and deliberations clearly
bringing out the reasons for recommending award, negotiations or discharge of the tender. In
doing so all members shall be unanimous and come to conclusion and sign jointly. In case of a
dispute the coordinating member (member of the department for which the tenders were invited)
shall sign his views and down below the other member or members shall record their descent
note and sign.
3.1.13 Accepting Authority: shall either accept or reject the tender committee
recommendations. In case he does not accept Tender Committee recommendations he shall
record his reasons in writing for not accepting the recommendations of any Member.
In case he accepts the tender committee recommendations a Letter of acceptance shall be
prepared in favour of the tenderer, got concurred by finance and delivered through registered
dak. Through this Letter of Acceptance the contractor shall be advised to deposit `Security
Money’ by a given time and to sign the agreement. He shall also be advised the completion
period of work. With this the contract is established pending signing of the Contract agreement.
The contract agreement shall be signed by an officer next below in rank to the accepting
authority, on behalf of the President of India, and by the contractor. The agreement document
shall include, i) Letter of Acceptance, ii) the original bid of the contractor with the negotiated
rates and conditions as mentioned if any by the bidder with his tender, and iii) All other
documents issued by railways to the tenderer which cover Special Conditions of Contract
(SCC), Instructions to the tenderer, specifications for work , specifications for material to be
supplied by the contractor and the General Conditions of Contract (GCC) for the railways in the
zone of the work is to be execute, as annexure.
3.1.14 Two Packet System: As per Railway Board’s directives for the works tenders having
cost more than Rs. 1 crore and upto Rs. 8 crores, as far as feasible, to call the tender on Two
Packet System. The powers to decide the matter has been vested with the General Manager. In
this system the tender document is divided into two parts. First part is the Credential Bid
covering qualifying criteria and Earnest money and the second bid is financial bid covering
Schedule of quantities and rates. The tenderer has to submit two envelops at the same time,
accordingly. The Credential bid is opened first, on which Tender committee after deliberations
shall decide the list of, valid, eligible and technically acceptable tenderer only. After the
acceptance of recommendations by Accepting Authority, the second bid shall be opened and
deliberated and accepted by the Tender committee and Accepting Authority respectively in the
same manner as ordinary tender. The biggest advantage of this system is that no biases can be
assigned for deciding a bidder to be eligible or not.
In private sector, concept of Q1 (Best Quality offer) has been adopted in place of L1 (lowest
cost offer). In this system only the best quality offer is accepted from the lowest cost bidder.
84
3.2
Limited Tenders: The Chief Signal & Telecommunication Engineer may prepare a list
of contractors with known sound credentials and financial health, in consultation with Finance,
Obtain approval of General Manger and resort to Limited Tenders. The list is updated and
modified from time to time. This system is used to cut short time and to seek contractors with
assured known credentials. The notice is issued only to the contractors born on the approved list.
However in this system open competition is eliminated and chances of higher rats increase.
3.3
Special Limited Tenders: May be adopted in consultation with FA&CAO for Works of
specialized nature (to be approved by the PHOD personally), for Works of Urgent nature (to be
approved by the GM personally) and for Consultancy works (to be approved by the GM
personally). Four contractors out of the Approved list for Limited Tenders maintained and some
more not born on the list of Approved List for Limited Tenderers subject to a minimum of six
contractors are selected and notified after Finance concurrence and approval of General
Manager. The balance procedure for award of the work is same as for other open tenders.
3.4
Post Contractual matters: The contact is awarded with the condition that the quantities
in the schedule are tentative and can vary to the extent of +25% or -25%, of the total cost of
contract without causing any change in the rates or any tender condition. The contractor shall be
bound to execute work for variation up to +50 %, in the cost of work as per contract with the
condition that if the agreement value goes beyond +25%, then for the first 15% increase in value
of the agreement, the rates shall be reduced by 2% of the incremental value and the rates shall be
further reduced by another 2% for the incremental value of the agreement for the next 10%
increase in the value for first 15% of the cost of contract, beyond 15%.
3.4.1 Variation in the items of schedule vis-à-vis cost of contract: One of the common, post
contractual matters is variation in the cost of contract. On receipt of the variation from the field,
first the vitiation of the contract shall be examined. It may happen that the total agreed cost of
contract may become higher than the total tendered cost of other tenderer when the revised
quantities are compared with the rates of all legible tenderers due to increase being of high value
items of schedule. Which shall mean that had the original quantities been as they are now after
variation, one of the tenderers other than the one to whom the contract was awarded, would have
been the lowest bidder and the contract would have been awarded to him. This shall vitiate the
entire process of award of the contract. To safeguard against such a situation the officer
executing the work shall keep a watch and permit variation of quantities only after ensuring that
the contract does not vitiate. If the contract does not vitiate the legitimacy and essentiality of the
variation shall be examined. Finding the variation to be inevitable, the sanction of the Contract
accepting authority shall be obtained.
3.4.2 Grant of extension for completion of work: The other common post contractual
matter is grant of extension to the Date of Completion (DOC) of the work as provided in the
agreement. The DOC can be granted only when applied by the contractor. There is no provision
for grant of DOC suo-moto. The DOC may be granted on account of delays in providing plans
or site of work or any other lapse on the part of railway. Such DOC shall be granted without
imposing Liquidate Damages and with the condition that neither the contractor shall be entitled
for any compensation nor the grant of extension of DOC shall alter any terms and condition of
the contract. The DOC extension may also be granted on account of lapses on contractor’s side.
85
In this case if the railway is satisfied that the lapses on contractor’s account are condonable,
DOC extension may be granted without Liquidated Damages, otherwise Liquidated Damages
may be imposed upon the contractor.
3.4.3 Contractor not applying for DOC: It is pertinent to note that a contract is valid and in
vogue only within its agreed date of completion. If the contractor does not apply for extension of
date of completion in time, railway shall be obliged to take action well before expiry of the
validity of the agreement, to terminate the contract against risk and cost of the contractor for
getting the balance part of work done without financial loss to the railway.
3.4.4 Request for change in rates or tender condition, from contractor: No change in
accepted rates and tender conditions is at all admissible after signing of contract agreement as
this shall vitiate the entire tender and require re-tendering.
3.4.5 Addition of new item of work during the course of execution: It may some times
happen that while executing the work some new work might be required to be done for
completion of the original work. For this a new schedule of work shall have to be prepared, rates
analysed and negotiated with the contractor, finance concurrence taken under approval of the
Contract Accepting Authority and sanctioned by the Contract Accepting Authority. This part of
work shall be allowed to be executed only after the same has been sanctioned.
3.4.6 Arbitration: Arbitration Act 1996 shall be applicable on all arbitration matters arising
after application of the Act.
i)
ii)
iii)
In case, the contractor feels aggrieved for any reason, he can opt for Arbitration. There
is an arbitration clause embedded in each contract which is usually derived from the
General Contract of Contract. It is during the progress of the contract or after
completion of the work that the contractor can invoke arbitration clause.
The contractor shall give in writing his claims of disputes and differences to the
accepting authority of the contract to be redressed. The accepting authority, within a
period of 120 days after receipt of the claims shall make and notify decisions on all
matters referred to by the contractor made in writing with reasons for accepting all or
some of the claims or rejecting all claims, to the contractor, and also that matters for
which provision has been made in clause 8 (a) , 18, 22 (5), 39, 43 (2), 45 (a), 55, 55-A
(5), 57 , 57 A, 61 (1) , 61 (2) and 62 (1) (b) of General conditions of contract or in any
clause of the special conditions of the contract shall be deemed as èxcepted matters’
and decisions of the Railway authority, thereon shall be final and binding on the
contractor provided further that èxcepted matters’ shall stand specifically excluded
from the purview of the arbitration clause and not be referred to arbitration.
The term Èxcepted Matters’ means the matters / claims èxcept’ which, the reaming
matters / claims shall be referable and referred to the Arbitrator for arbitration. The
matters for which there already is one or more clauses in the agreement i.e. the Special
Conditions of Contract (SCC) or clause numbers 8 (a), 18, 22 (5), 39, 43 (2), 45 (a), 55,
55-A (5), 57, 57 A, 61 (1), 61 (2) and 62 (1) (b) of General Conditions of contract of the
railway in the zone of which the work is awarded, in which conditions are laid down to
deal with such a situation, as under the dispute / claim.
86
iv)
v)
The reply to the contractor in such a case shall be given in association with Law Officer
and Finance and finally having obtained the approval of General Manager. The claims
falling within the ambit of Èxcepted Matters” shall be specifically mentioned giving
grounds and referring to the clause under which the claim is found to be excepted
matter. It also shall be mentioned that in case of matter being referred for arbitration the
claims falling within the purview of excepted matters shall not be referred for
arbitration.
On getting the reply from railways, if the contractor is still not satisfied or does not get
any reply form the railway within the specified period, the contractor after120 days but
within 180 days of his sending letter of claims, shall request to the General Manager
who is the sole arbitrator, for appointment of Arbitrator. Single arbitrator or the Arbitral
panel of more than one arbitrator shall be appointed by the General Manager depending
upon the value of the claims. In case of appointment of arbitral panel of more than one,
one member shall be from Finance and if there is another member it shall be of the
choice of the contractor seeking Arbitration.
3.4.7 Appointment of Arbitrator and proceeding: The Arbitration proceedings are
governed under Arbitration and Conciliation Act 1996. It is advisable that during the arbitration
proceedings assistance of an Advocate, born on the panel of railway for arbitration, be taken.
Although the arbitration proceedings do not follow the procedure of court but in case either
railway or the contractor approaches court of law against arbitration award, any of the legal
lapses may not be used against the interest of railways.
After hearing both the parties the Arbitrator / or the Arbitral panel shall give award, discussing
in details the reasons for having arrived at the reason for accepting or rejecting the claim, claim
wise on a stamp paper of the value of Rs.1/- per Rs. 1000/- upto Rs. 5000/- and Rs.0.75/- beyond
Rs.5000/- subject to a maximum of Rs. 75/-in Delhi, of the awarded value or of the value as
decided from time to time and in different states.
The award so received shall be forwarded for General Manager’s approval through Law officer
and finance. The General Manager may accept the award in full or decide to appeal against the
award. If the award is accepted in full or part thereof, the payments shall be made to the
contractor within time as stipulated in the award. For the unaccepted part of the award the appeal
in the High Court shall be made by the contract accepting authority.
4.
Execution of work on a running line:
4.1
Notification to Railway officials before opening works: [SEM 1988 -9.2] No
signalling work affecting the running of trains or working of traffic at a station shall be brought
into use until staff of all concerned departments have been notified by means of a circular issued
by the Operating Department. Timely intimation of the date of commencement of work, duration
of work, arrangements for working of trains during the progress of the work, date of opening of
the work, etc., shall be given to the Operating department, whenever any new or revised traffic
working instructions are to be brought into use to enable Operating department to give the
station and running staff due notice.
87
4.2
Works requiring notice to and sanction of the Commissioner of railway Safety:
[SEM 1988-9.6] Under section 20 of Indian Railway Act and chapter VI of the `Rules for
Opening of a Railway or section of Railway for public carriage of passengers’ (See paragraph
5.3.2 & 5.4 of this chapter) the approval of Commissioner of Railway Safety is required for the
execution of any work on the open line which will effect running of passenger train and any
temporary arrangement necessary, for carrying it out except in cases of emergency. The
following signal and Interlocking works, when they are connected with or form part of a
Railway already opened for carriage of passengers, require the sanction of Commissioner of
Railway Safety before they are commenced or opened:
4.2.1 Additions, extensions or alterations to existing Block, Signalling and Interlocking
installations,
4.2.2 New Block, Signalling and Interlocking installations,
4.2.3 New stations temporary or permanent,
4.2.4 Interlocking of level crossing, catch siding slip siding, etc.
4.3
Application for sanction: When the work as mentioned above is to be executed by
Divisional organisation, Application to the Commissioner of Railway Safety shall be made by
Divisional Railway Manager and when the work is to be executed by extra Divisional
Organisation such as construction organisation, the application shall be made by an officer not
below the rank of Deputy Chief Signal & Telecommunication Engineer for signalling works.
For joint works the application shall be made by an officer not below Junior Administrative
grade of the department which controls the work.
The application prepared in the format given below, shall be accompanied with the Signal &
Interlocking plan, Interlocking table or selection table and Station working rules for Signalling
works and submitted to the Commissioner of Railway Safety at least fifteen days in advance of
expected date of commissioning. The sanction shall expire if not brought into use within one
year of the date of sanction. The format for making the application is given below:
Application for Sanction
………………..RAILWAY
Department……………………..….…..
Office………….….....…...
No……………………………..…….…
Dated…………..…….......
From
The………………………….
Designation…………....…....
To
The Commissioner of Railway Safety,
……………………………………….
Sir,
I hereby apply for your sanction to*…………………………….....................................................................
……………………………………………………………………………..……………….……..……..….……...……
being commenced and opened for the public carriage of passengers when ready.
2. With reference to Chapter VI of the rules for the opening of a Railway, I have to enquire whether you wish to
inspect the work prior to its opening for the public carriage of passengers, in which case intimation will be given of
the date completion.
3.
In the event of your deciding to not inspect the work prior to opening, the Engineer-in-charge will, on
88
completion of the work, submit the Safety Certificate, duly signed by him, prior to the opening of the work for
public carriages of passengers and when required, also dispatch a telegram ** to your address intimating that the
work has been opened and the safety Certificate has been signed by him.
4. The application for the use of locomotives and rolling stock to be drawn or propelled thereby on the proposed
line, in accordance with Section 16(1) of the Indian Railways Act (IX of 1890), is sent herewith/not required.
5.
I.
II.
The following documents @ are enclosed:
Temporary Works:
a) Description of proposed work.
b) Drawing of temporary work.
c) List of infringement to Schedule of Dimensions.
d) List of deviations from the Signal Engineering
Manual.
Permanent Works:
a) Description of proposed work.
b) Drawing of temporary work.
c) List of infringement to Schedule of Dimensions.
d) List of deviations from the Signal Engineering
Manual.
e) List of deviations from General and Subsidiary
Rules.
f) Restrictions.
g) Rules for Traffic Working.
h) Document for Bridges as per Chapter VII of the
Rules for the Opening of a Railway.
e) List of deviations from General and Subsidiary
Rules.
f) Restrictions.
g) Rules for Traffic Working.
h) Document for Bridges as per Chapter VII of the
Rules for the Opening of a Railway.
6. Certified that a detailed examination of the strength and arrangement of the materials to be used in the
temporary permanent works in above connection, have been made and that the design and the materials to be used
are up to the loads, which they will be required to carry and that their opening for public carriage of passengers will
not be attended with any danger.
(Delete temporary or permanent work, as the case may be)
Yours faithfully
Signature….…………………......
Designation.…………………......
Dated…..….…………………......
No…………………..
From
………………………………………..
Sir,
Your No……………………………………………………
Sanction is accorded to the above work being carried out. % I do not propose to inspect the work prior to
its opening for the carriage of passengers. When ready, it may be opened on a Safety Certificate (vide Paragraph 3 of
your letter) which should be submitted to me direct without any delay.
% I propose to inspect the work prior to its opening for the carriage of passengers. Advice of the date,
when work will be ready for inspection should be intimated at least 14 days before it is proposed to open it.
…………………………………………………
Commissioner of Railway Safety
* Here enter the name of work and mention whether permanent or temporary.
** Form of telegram: “Reference sanction No……………dated……………………work open at for public traffic on
…………………………First train to pass………………………No danger to public. Certificate signed.”
@ If any to the documents are not sent, then ‘NIL’ to be written against such items. Working rules for extensive remodelling scheme may be send in not later than one month before the date on which the work is to be brought into
use, and in such cases “will follow” should be written instead of “NIL”.
% Strike out paragraph not applicable.
89
In case of any material deviation from the plan approved by the Commissioner of Railway
Safety, which affects yard layout or signalling and interlocking arrangements or system of train
working, prior approval of Commissioner of Railway Safety shall be obtained before opening of
the work.
4.4
Preparation for Commissioning:
4.4.1 While according sanction the Commissioner of Railway Safety shall advise in writing
that whether he proposes to inspect the work before commissioning or not to inspect the work
prior to opening.
4.4.2 In case the Commissioner of Railway Safety proposes to inspect the work prior to
opening he will communicate his sanction to open the work in writing after inspection.
4.4.3 In case the Commissioner of Railway Safety does not propose to inspect the work prior
to opening, the Engineer in charge, after fully satisfying himself that the work has been executed
in conformity to approved plans and is safe for public carriage of passengers without
endangering safety of the passengers, shall submit Safety Certificate, signed by him prior to
opening of the work. The certificate shall be signed jointly in case of joint work. The safety
certificate shall be counter signed by the officer who applied for the sanction of the
Commissioner of Railway Safety. The formats for both safety certificates are given below:
Safety Certificate
………………..RAILWAY
When the Commissioner of Railway Safety does not inspect the work prior to opening, this certificate must
be signed before opening temporary or new works.
From,
The Divisional Railway Manager/Deputy Chief Engineer (Construction)/Deputy Chief Signal and
Telecommunication Engineer (Construction),…………………….Division.
To,
……………………………………….
Description of work..…………………………...............................................................................................
…………………………………………………………………………..……………….……..……..….……...……..
Reference: Divisional Railway Manager
Chief Engineer/Deputy Chief Engineer (Construction),
Deputy Chief Signal and Telecommunication Engineer (Construction).
Application………………………………dated………………..Sanctioned under Commissioner of Railway
Safety No…………..dated………………..to commence and open the above work.
Following Permanent/temporary work has been done……………………………………………………………………………..……………….……..……..….……...……..
……………………………………………………………………………..……………….……..……..….……...……..
I/We do hereby certify that, in the work abovementioned(i) The schedule of Dimensions has not be infringed* except in regard to the items sanctioned under
letter* No…………...dated…………………
90
(ii) Engineering work has been carried out in accordance with plan No……………….* except in regard
to the alterations sanctioned under letter No……………dated……………….
(iii) The weight of rails, strength of bridges and general structural character of the works are such as
have been prescribed under the rules.
(i) The *Signalling and *Interlocking and Block Signalling has been carried out in accordance with
Signalling Plan No………………and the requirements and instructions laid down in the Signal Engineering Manual
have been completed* except in regard to the items sanctioned under letter No……………..dated……………..
2. A certificate form the Divisional Safety Officer/……………………stating that the necessary working
rule have been issued and giving reference in regard to sanction to deviation (if any) from General and Subsidery
Rules is attached/not required.
*To be scored out if not applicable.
3. I/We hereby certify that on the……………………..19……………, I/We have carefully inspected and
tested the above work and that I/We have satisfied myself/ourself that it has been properly completed and is in good
working ‘order’ *and that the work can be opened for public carriage of passengers without endangering the safety of
the travelling public, or of the employees of the Railway subject to the following speed restrictions:
@Temporary…………………….km.p.h………………….due to…………………………………………..
@Permanent…………………….km.p.h………………….due to………………………….………………..
4. The work is being opened on………………………………………………………
*Necessary in case of signalling and interlocking works only .
@ To be scored out if not applicable.
………………………………………………..…..
Assistant Engineer
Dated……………………..……..19………….…..
Countersigned by:
…………………………………..
Dated………………….19………
…………………………………………………....
Assistant Signal and Telecommunication Engineer.
Dated……………………..……..19………….…..
Countersigned by:
…………………………………..
Dated………………….19………
Countersigned by:
…………………………………..
Dated………………….19……….
No………………………………
Dated………………….19……….
Countersigned and forwarded to Commissioner of Railway Safety for information:
1.
2.
3.
4.
5.
Divisional Railway Manager/
Chief Engineer (Construction)
Deputy Chief Signal and Telecommunication Engineer (Construction).
91
Safety Certificate for S&T works for introducing Electrification
It is herby certified that the Signalling and Telecommunication work to be executed for the purpose of
introduction of 25 KV signal phase, 50 cycle AC/1500V DC traction between……………..and…………..
on……….. Railway have been carried out properly and that electric traction can be introduced for public carriage of
passenger without endangering the safety of the travelling public or of the employees of the Railway subject to
maximum value of traction current not exceeding…………Amps.
Name:
Designation:
Joint Safety Certificate
Certified that it is safe to run………………….(Particulars of locomotives and rolling stock proposed to run)
not exceeding………………unit (in the case of locomotives) coupled together on the section
(station)……………........... to…………………..(station) from………..……..(Km.) to…………..…..(Km.) of
the………..…… Railway at a maximum speed of…………….(Km.p.h.) against a maximum speed
of…………….(Km.p.h.) certified by R.D.S.O. subject to the following speed restrictions and conditions:
a)
b)
Speed Restrictions:
Sl. No.
From Km. to Km.
Nature of speed restriction
Brief reason for restriction
Special Conditions:
C.M.E.
C.E.E.
C.E.
C.S.T.E.
C.O.P.S.
Notes: 1) When the speed of a loco/rolling stock is to be increased the C.O.P.S. and C.S.T.E. should be associated
when the increase in speed is contemplated over the maximum sanctioned speed for that category of train (Passenger
and Goods) over a particular section.
2) C.E.E. should countersign wherever electric traction is involved.
4.4.4 The Engineer in charge shall bring the installation in use by issuing a message on the
format given in the application for sanction, marked as **.
4.4.5
The safety certificate along with a certificate from Operating department stating that
Station working rules have been issued shall be sent to Commissioner of Railway Safety
endorsing copies to Divisional Railway Manager and Chief Signal & Telecommunication
Engineer. Copy shall also be endorsed to Chief Engineer if engineering Department is also
involved with the work.
4.5
i)
ii)
Commissioning of the work: Whenever a new track is laid, it is easier to execute the
work without bothering about the existing rail traffic. However great care is required to
be taken while working on a track or station where rail traffic is already there:
Safety of men working; arrangements must be made to warn persons working on or
around the track by whistling. One person shall specifically be deputed for this purpose.
Safety for existing train traffic: No attempt shall be made to make any alterations to
existing system, to suit or to accommodate new installation before switching over from
existing to new system of working i.e. wiring, replacement of point machines with
another type, interlocking in the lever frame, modifying existing signal to suit future
requirements or even shift existing wiring temporarily to another set of terminals to get
92
iii)
the terminals free for new work etc, howsoever un-important or redundant that may be,
and even after observing proper procedure such as under disconnection memo or under
the supervision of open line representative. Entire new arrangement should be totally
isolated with the existing arrangement.
All new signals shall be provided with a cross on their front side. The size of the cross
shall be one metre in length and 200 millimetres in breadth, painted white. See Fig. 4.5.
Fig. 4.5
Signals not in use provided with cross
iv)
Temporary Working Instructions shall be prepared for working traffic at the station,
during the period the station is non-interlocked for introduction of new system,
4.6
Declaring the station Non-Interlocked: When the entire work is ready for
commissioning, the sanction of Commissioner of Railway Safety has been received, and a date
for non – interlocking the station has been decided, speed restriction shall be imposed for trains
to move at speed of 15 kilometres per hour, across the station during the period of noninterlocking of the station. The station shall be declared non-interlocked with the consent of the
Traffic Inspector, by the section Engineer responsible for maintenance of the station. For this a
disconnection memo for interlocking of the station, shall be put up to the Assistant Station
Master, on the prescribed form. The station shall stand non-interlocked with the acceptance of
the disconnection memo.
Besides prescribed speed of the section, permanent or temporary speed restrictions are required
to be imposed in the Station Section or Block Section. In Station section the speed restriction is
required to be imposed for signalling works, when the station is non-interlocked either for
overhauling of interlocking or when the existing system is to be replaced with a new system of
signalling, affecting the existing interlocking arrangement. In block section the speed restriction
is required to be imposed for track renewal works, maintenance of track culverts or bridges or
for any other contingencies.
The Section Controller of the section shall be intimated at odd hours on the date on which the
station is scheduled to be non-interlocked so that notice for the speed restriction may be issued
93
to all Loco Pilots passing the said station, at the stopping station, in time without making them
stop in between, on stations other than `Notice stations’.
4.7
Fixing of Caution, Speed and Termination Indicator Boards: Caution, speed &
termination indicator boards shall be provided at the station simultaneously along with
imposition of speed restriction. These boards shall be lighted during night time, the speed
restriction being temporary, required during the non- interlock period only. These boards are not
required to be lighted during night time in case of permanent speed restrictions:
i)
ii)
iii)
Caution Indicator: In each case a caution indicator, 1400mm long and 400 mm wide
with fish tailed at one end and pointed at the other end, painted in yellow and black (see
fig 4.7) and mounted on a post painted with black and white strips of 300mm, shall be
fixed at 800 metres from the point where restriction of speed has to commence. In case
the stop dead restriction is there, the distance shall be 1200 metres instead of 800 metres
on Broad Gauge. This indicator shall be used for permanent as well as temporary speed
restrictions. When used for temporary speed restriction, the indicator shall display two
yellow lights by night, facing approaching train or painted with luminous paint or
provided with fluorescent tape. The indicator shall be mounted at the height of 2 metres
from the rail level.
Speed Indicator: This indicator shall be followed by a `Speed Indicator’ with speed
painted in black on a equilateral triangular board of 1 metre arm, painted yellow, which
shall be mounted on a post painted with black and white strips. A lamp shall be provided
on the post such that the speed written on the speed board is properly visible to the
approaching train Loco Pilot. The Speed Indicator shall be mounted near the foot of first
reception signal, at a height of 2 metres from rail level, for signalling works
Termination Indicator: Two Termination Indicators shall be provided, one for
passenger trains and other for goods trains painted black as T/P and T/G with 2500mm
high and 40 mm thick letters, for passenger and goods trains respectively, on a circular
disk of 1 metre diameter, painted yellow and mounted on a post painted in white and
black strips of 300 mm. These indicators shall be fixed at a distance of longest
passenger train and longest goods train respectively, running on the section, from the
point the restriction ends. A distance of 670 meters is considered adequate to cover the
length of longest goods train. These indicators shall be suitably lighted by fixing a hand
signal lamp on the post at a height of 1650 mm from the rail level.
T/P
10
T/G
Fig. 4.7
Caution indicator, speed indicator, passenger train termination indicator & goods
train termination indicator respectively from left to right
94
Adequate communication between the controlling Station Master and the Assistant
Station Masters posted at each point or group of points for ensuring proper and right
setting and locking of points, shall be provided.
4.8
i)
ii)
iii)
iv)
Switching over of new signalling system replacing the existing:
A programme for switching of the old system of interlocking shall be chalked out to
ensure replacement without causing hindrance to train movement maintaining absolute
safety during the station is non- interlocked. Switching of new system shall be under
taken in accordance to the pre-chalked out programme. Disconnection memos shall be
given for equipment for replacement with the new one and reconnected through
reconnection memo accompanied with a note that old equipment has been replaced with
new one. All these disconnection and reconnection memos duly acknowledged, shall be
kept in safe custody by the Section Engineer. The process shall continue till all the
existing equipment due to be replaced with the new one, have been replaced.
The Traffic Inspector shall take assurance from all the Assistant Station Masters,
proposed to operate the new system of working and have taken learning, on a register
meant for the purpose.
After the new system has been introduced, the signals and other equipment rendered
surplus and likely to obstruct the visibility or any other function shall be dismantled
without delay. New system shall be tested to be in exact conformity with the Signal and
Interlocking Plan and the interlocking table or the Selection Table, on which sanction
has been accorded by the Commissioner of Railway safety to open the work without
inspection by him and that the officer concerned not below the rank of Assistant Signal
& Telecommunication Engineer or any other officer authorised under approved
instructions, is fully satisfied of smooth and safe working, shall ensure that the
assurance from the Assistant Station Masters has been taken by the Traffic Inspector,
shall declare the station having been commissioned to new system of working. He shall
then issue a telegram form the station itself notifying so and record the number and
name of the first train to pass through the station immediately after bringing the new
system in use.
The officer concerned declaring the station commissioned shall make entry in the signal
failure register mentioning the number of Signal and interlocking plan brought into use,
the number of the sanction accorded by the Commissioner of Railway Safety and the
numbers of Block instruments if changed and put his signatures with date.
5
Execution of new lines and Electrification works:
Rules for Opening of a railway or section of a railway for the public carriage of
passengers: ‘Rules for Opening of a Railway or Section of a Railway for the Public Carriage of
Passengers’ are issued by Railway Board. It is pertinent to note that these rules cover `public
carriage of passengers’. New railway line include extensions of existing railways, new double
treble or other running lines laid alongside existing lines and conversion of gauge to another or
installation of electric traction on the existing lines.
These rules contain fine details essentially required to be known for execution of new works.
These rules are not covered elsewhere in other rule books and manuals and the signal
engineering is incomplete in absence of knowledge of these rules. Some of the major guidelines
95
with reference to the chapter of the book covering `Requirements and Recommendations for
Signalling and Interlocking Installations are discussed here:
5.1
Preparation for opening of new railways:
5.1.1 Whenever the General Manager of a Zonal Railway or Chief executive of a nongovernment railway is of the opinion that any railway or a part thereof is required to be opened
for public carriage of passengers, he shall refer the matter to the Chief Commissioner of Railway
Safety, for inspection and report on the safety of that railway.
5.1.2 Every Railway administration shall ensure that the railway line or portion thereof to be
opened for public carriage of passengers is complete in all respects as per the Indian Railway
standard Codes and manuals of practice or as per the Codes and Manuals of Practice as
specifically approved by Central Government for that Railway and for such opening all the
administrative formalities are complete and that the working of the railway is regulated by the
Indian Railway (Open Lines) current General Rules or any other General rules as approved by
the Central Government and notified in the Gazette of India.
5.1.3 The Chief Executive of the railway administration of non-Government Railway, before
making a reference to the Chief Commissioner of Railway Safety for inspection of any railway,
shall obtain a clearance from the Central Government that the railway which is sough to be
opened has been constructed and maintained by that administration in accordance with the
Indian Railway Standard Codes and Manuals of Practice and working of the railway is governed
by the Indian Railway current General rules.
5.1.4 Before a reference to the Commissioner of Railway Safety, it shall be ensured that the
railway proposed to be opened, is operationally fit in every respect before inspection and while
making a reference to the Commissioner of Railway Safety he is advised of any deviation in
design, material & construction of work, rolling stocks or appliances of the railway, instances in
which maximum and minimum dimensions have not been observed, or the bridges, tunnels are
not capable of carrying the prescribed or standard load without exceeding the stress specified in
the Indian railway standard Codes & Manuals of practice.
5.2
Supply of documents to the Chief Commissioner of Railway Safety:
5.2.1 The General Manager of the Zonal railway or the Chief Executive of non- Government
railway, while making a reference for inspection to the commissioner of railway safety, shall
furnish tabulated details, Index plan & section of railway, Drawing of works, List of question
and answers, certificates, List of infringements of Maximum & Minimum dimensions, Working
orders to be enforced at each station and Administrative note giving the salient features of the
project. The work could be Engineering, Signalling or Overhead traction in nature however all
these documents shall be discussed with reference to signalling works here.
5.2.2 Contents of the documents to be supplied as mentioned above:
i)
Tabulated details shall consist of important characteristics of the railway or the portion
of the railway to be opened for public carriage of passengers and in particular shall
include gradient abstract, stations and station sites, station machinery, level crossing
abstract, brief particulars of traction installations, power supply installation abstract etc.
ii)
Index plan & section sheet shall be prepared as laid down in Indian railway code for
Engineering Department as reproduced in schedule and shall include Diagrammatic
plans of tracks and particulars of turnout, block working & of any signals & interlocking
installed.
96
iii)
SN
1
2
3
4
5
6
7
8
iv)
List of questions & answers shall be prepared for signalling items as tabulated below:
QUESTIONS
Have the requirements and recommendations for Signalling and Interlocking, and the
catechism for signalling and interlocking installations vide chapter VII of these rules,
and the appendix thereto, being fully complied with, according to the class of signalling
and interlocking installed? If not, in what respect do the arrangements provided fall short
of them?
Have the requirements and recommendations for Signalling and telecommunication
installations in accordance with the instructions issued for the installations of S&T
equipment in 25KV 50 Hz electrified sections been complied with? If not, in what
respect the arrangements provided fall short of them?
Is provision made, whether by trap points or other means, to prevent vehicles standing
on sidings, from fouling any running line?
Are there any stations situated on a grade steeper than 1 in 400? If so, what special safety
devices are adopted and / or special rules enforced at those stations? (No station should
be constructed nor should any siding join a passenger line on a grade steeper than 1 in
260, except where it is un avoidable, and then only with previous sanction of the
Railway Board obtained through the Commissioner of Railway Safety, when a slip
siding or other arrangements are made, sufficient to prevent accidents.)
What safety sidings are provided? Are any other necessary? (At any station situated in
the immediate neighbourhood of an incline steeper than 1 in 100 falling away from the
station and 1 in 80 falling towards the station, a catch siding in former case and a slip
siding in later case, should be provided if necessary, in suitable position. The take ‘Off’
points to catch siding or a slip siding should normally be set and locked for the siding
except where required to be trailed through.
Are station yard so arranged that shunting past junction or level crossings may be
avoided as far as feasible?
Are shunting necks for goods working provided in large yards, where shunting
operations cannot otherwise be carried on without interfering with incoming trains
Are means of communication between passengers and the guards provided in all trains
carrying passengers?
ANSWERS
Certificates of the work shall comprise Maximum & Minimum dimensions,
Communication, System of working, Working order to be enforced at each station on
the railway to be opened, prepared in accordance with the rules provided in the chapter
V of General & Subsidiary Rules specifying any special conditions that are required to
be met with.
The format of the certificate to be given by the General Manager shall be as follows:
I do hereby certify:
(i)
that the Maximum dimensions for railways in India have in every case been worked to, with the
exceptions detailed in the statement herewith annexed, also that the Standard dimensions will be observed in
future, and that no work or structure infringing the standard dimensions will hereafter be permitted without the
sanction of the Central Government. (In the statement showing the cases in which the maximum and minimum
dimensions have been infringed, full details for each case must be given, in the form given below, with the
explanation of the necessity for such infringements and a reference to the authority under which it was permitted.
If there have been no infringements of the maximum and minimum dimensions the words “with the exception
detailed in the statement herewith annexed” should be omitted or struck out. This form XVII shall be annexed to
the certificate)
ii)
that each bridge is of such design, dimension and construction as will enable it to bear the dead load of
the structure itself (with flooring, roadway, permanent way etc. complete), and in addition thereto, the equivalents
97
of the live loads specified in the rule prescribing Standards of Design and loading for Railway bridges, without
exceeding the maximum permissible stress on the available material in any member or portion of the structure.
iii)
that more than two engines shall not under any circumstances be allowed at one time on the same track
of one span of any bridge.
iv)
that every coaching vehicle constructed or procured for the use of the railway in mail and passenger
trains is, and shall be provided with vacuum/air brake and effective means of communication between passengers,
guard and driver. (This part of certificate is nor necessary for those light lines on which the use of vacuum or air
brake has not been insisted upon.)
v)
that one compartment or such number of berths or seats, as the railway administration may think fit, of a
second class carriage of every train carrying passengers shall be reserved for exclusive use of females.
vi)
That the railway shall be worked on the system known as Absolute Block System in accordance with
the regulations prescribed in Chapter VIII of the General Rules for railways in India.
vii)
That the electric traction equipment can be used for public carriage of passengers without danger to
public and that the rules for design and inspection of equipment for electric traction (of Chapter VIII of these
rules) have been complied with. (This shall be included only when applicable.)
viii)
That the signalling and telecommunication equipment have been installed in accordance with the
approved instructions and they are safe for passing traffic.
ix)
That……….has been delegated to accompany the Commissioner of Railway Safety on his inspection
and all information supplied or engagements entered into by him shall bear my authority.
(Signed)
The General Manager
FORM XVII
INFRINGEMENT OF MAXIMUM AND MINIMUM DIMENSIONS
SECTION:
LENGTH:
SN
RAILWAY:
GAUGE:
Location
Division
Kilometrage
Name of
structures
which
infringe
Prescribed maximum
&
minimum
dimensions
Chapter
Maximum
item
Minimum
Existing
actual
dimension
Amount
of
infringe
ment
Particulars of
sanction
to
infringement
& remarks
5.3
Inspection by Commissioner of Railway safety:
5.3.1 Special arrangements shall be made by the General Manager to facilitate the inspection
by the Commissioner of Railway Safety and also give all information and assistance in his
power, and provide all instruments and apparatus required for making measurements, testing of
bridges and electrical and other installations, of the railway, which is to be opened.
The General Manager shall, on receipt of the a request from the commissioner of Railway
Safety, make arrangement to dismantle any structure on the railway to be opened, with a view to
make complete examination of the details or workmanship of the structure as quickly and
completely as possible. The Commissioner of Railway Safety, while requesting the dismantling
shall be responsible to see that such complete dismantling is essentially required for its proper
inspection.
The General Manager shall accompany the Commissioner of Railway Safety throughout
inspection or under unavoidable circumstances he shall authorise an officer, not below the rank
of Under Secretary to the Government of India authorised by general or special order of Central
Government issued under section 28, to accompany the Commissioner of Railway Safety during
the entire period of inspection.
98
During the inspection the engineer or officer, immediate in-charge of the corresponding section
may also be present.
5.3.2 Sanctioning of opening of railways and opening of Railway for public carriage of
passengers: The Commissioner of Railway Safety shall submit his inspection report to the
Central Government along with Index plan, tabulated details, list of question and answers,
certificate by the General Manager, & list of infringements as submitted by the General Manger
while making the reference along with results of the bridge test.
The Central Government after considering the inspection report of the Commissioner of Railway
Safety, sanction the opening of the railway or a portion of the railway for public carriage of the
passengers giving due consideration to the suggestions or conditions subject to which the
Commissioner of Railway Safety has recommended the opening of the railway.
Where Commissioner of Railway Safety has not recommended the opening of any railway, or
has proposed to cancel the sanction already give, the Central government shall confirm , modify
or cancel the sanction given to opening of such railway or a portion of the railway and shall take
steps to remove the defects or the shortcomings pointed out by the Commissioner of Railway
Safety in his inspection report in case of Government railway, and direct the General Manager
concerned to rectify the defects, in case of nongovernment Railway.
In case it is not possible to remove the defects the Central Government shall order closing of the
railways for the public carriage of the passengers, which can be reopened unless the same is duly
inspected and recommended by the Commissioner of Railway Safety for its reopening.
The actual date of opening of the railway line or a section thereof for passenger traffic shall be
notified by the concerned General Manager, after consulting the Central Government, by
notification in the Official gazette, and in local news papers of the area through which the
railway passes.
5.4
Temporary opening of railways by the Commissioner of Railway Safety:
The Commissioner of Railway Safety may sanction the temporary opening of new railway lines
for public carriage of passengers, subject to such conditions as he may impose during his
inspection in the interest of the passengers. The Central Government may confirm, modify or
cancel the sanction given subject to such conditions, alterations or relaxations as may be
considered necessary, on receipt of inspection report of the Commissioner of Railway Safety.
5.5
Opening of minor works:
5.5.1 Where it is proposed, on the railway which has been opened after inspection, to
construct any deviation lines, stations, junctions or level crossings, or to make any addition,
alteration or reconstruction materially affecting the character of any work and such work forms
part of, or is directly concerned with the working of that railway, the railway administration
concerned shall give notice to that effect to the Commissioner of Railway Safety.
Every temporary deviation line irrespective of its length and any permanent diversion less than
two kilometres in length where no new station is involved shall also be treated as new minor
works.
99
5.5.2 Before any such work, the execution of which may affect the running of trains carrying
passengers, is taken in hand, the concerned railway administration shall furnish drawings or
particulars of the work and of any temporary arrangements necessary for carrying it out, to the
Commissioner of Railway Safety for his approval.
5.5.3 In case of accident temporary diversions may be opened after responsible person of the
concerned railway certifies that the use of such diversion will not cause danger to passengers or
to the railway servants. However where the use of the temporary division is likely to be
extended to for more than three days, the Commissioner of Railway Safety shall take action to
inspect the diversion at the earliest opportunity.
5.5.4 Powers of Commissioner of Railway Safety to open minor works:
The Commissioner of Railway Safety may sanction for opening any minor work for passenger
traffic, without previous notice, if he is satisfied that work may be allowed to be opened, either
with or without inspection.
(i)
The Commissioner of Railway Safety shall take steps for carrying out inspection
subsequently, for the work opened without inspection.
(ii)
The authority for opening any work shall be communicated in writing by the
Commissioner of Railway Safety to the concerned railway administration and a record
of all works so authorised during each year, with particulars of prior or subsequent
inspection, if made, shall be maintained by the Commissioner of Railway Safety.
5.5.5 Infringement of maximum and minimum dimensions: No infringements of
Maximum and minimum dimensions shall be permitted without the prior sanction of the
Commissioner of Railway Safety or of the Central Government.
5.5.6 In case of application for use of new type of locomotives or rolling stock
contemplating increase in the speed of loco/ rolling stock over the sanctioned speed for a
specific category of train over a particular section of the railway, the certificate in the
application shall also be signed by Chief signal & Telecommunication Engineer & Chief
Operating Manager of the Zonal railway concerned; on the railway where both shop
maintenance and open line maintenance of electric locos and electric Multi unit rolling stock are
under the control of electrical department only, the Chief Electrical Engineer, other wise Chief
Mechanical Engineer should also sign; when motive power with chopper control is to be used
the Chief Signal & Telecommunication Engineer and Chief Electrical Engineer should sign the
certificate, in addition to the signatures of Chief Engineer.
5.5.7 In case railway administration which desires for use of new type of block instruments
or main signalling instrument, which is not of approved type, shall apply for sanction of the
Commissioner of Railway Safety. The application must be accompanied with (i) A
list
of
requirements which the instrument fulfils, together with the results of the field trial conducted by
the railway concerned; (ii) A certificate by Chief Signal & Telecommunication Engineer in the
form as given below; (iii) A statement whether the equipment complies with the specifications
approved by the Central Government; (iv) A statement giving comments on the performance of
the equipment as a result of bench trails (trails done in the laboratory) conducted by Research
Designs & Standards Organisation (RDSO) (vi) The circuit diagrams and other relevant
diagrams and explanation as may be necessary to give full particulars of the principles of
operation and safety features incorporated & (vii) A copy of the instructions approved by the
Chief Operating Manager, to be issued for operation of the equipment by the operating staff,
including those instructions for working under abnormal or failure conditions.
100
CERTIFICATE
Certified that it is safe to use (particulars of the equipment) at the station/ on the section of railway,
with the following precautions:1.
2.
3.
4. etc.
( Sd/-…)
The Chief Signal & Telecommunication Engineer.
5.6
5.6.1
i)
ii)
iii)
iv)
v)
vi)
vii)
5.6.2
i)
ii)
iii)
iv)
v)
Requirements and recommendations for Signalling and Interlocking Installations:
Signals:
The number of signals provided and their height should be limited to what is actually
necessary for safety and traffic purposes.
The distance between Distant/Warner and the first stop signal ahead shall be such that a
train approaching the Distant/Warner signal at the maximum permissible speed with due
allowance to weight, braking power, gradient and sighting distance can be stopped
before passing the first stop signal.
The subsidiary signals shall be readily distinguishable from running signals.
Where a signal or its back light is not visible to the railway servant operating the signals,
the aspect of the signal and the condition of the light shall be repeated at the place of
operation.
It is desirable that the signalling at all block stations and interlocked level crossing gates
in the same section shall conform to the same standard and type.
Signals shall be so designed as to give the most restrictive aspect in the event of failure
of any part of the mechanism, which operates them. This feature is called fail safe
feature of the signalling system.
The location and type of signals shall be in accordance with the provisions contained in
chapter VII of Signal Engineering Manual and Chapter III of General rules 2007.
Points:
Points must be so located that movement over them shall be within view of the cabin or
other location from which they are worked, unless an approved alternative for direct
vision by the cabin man i.e. electric indication is provided.
The points, locks and bars shall not be worked by wire but by rodding or power
operation.
Spring points shall not be used.
Movable crossings and movable diamond crossings on passenger lines shall be provided
with complete facing point equipment of approved type.
The requirement of points as stipulated in chapter VII of Signal Engineering Manual
shall be followed.
5.7
Interlocking:
5.7.1 Signal & Interlocking apparatus and installations shall be in accordance with chapter
VII of Signal Engineering Manual.
5.7.2 Apparatus provided for operation and control of signals, points etc shall be interlocked
101
and arranged to comply with the essentials of interlocking and other requirements as laid down
in chapter VII of the Signal Engineering Manual, Part-I.
5.7.3 The operation of the signalling gears may be from a lever frame or a panel with
individual operation of points, signals and other functions of a providing operation of a
route setting type or other approved means in accordance with the provisions of Chapter
VII of the Signal Engineering Manual, Part-I.
5.7.4 When a signal is controlled by more than one agency, it shall be possible for every such
controlling agency to replace the signal to ‘On’ position.
5.7.5 The Station Master shall be provided with interlocked mechanical or electrical control
of the Home & last stop signals except where i) all reception lines are fully track circuited from
Home Signal to corresponding Last Stop Signal on double line and Home Signal to Home
Signal on single line, or All reception lines are track circuited from the fouling mark to fouling
mark and the non-track circuited portion of the line from the fouling mark to Home Signal is
within the range of visibility of the Cabin Assistant Station Maser /Leverman/Switchman, ii)
Station Master does not allot the line; and iii) Cabin Assistant Station Master/ Switchman posted
in the cabin operates the block instruments and controls reception/despatch signals.
5.7.6 Standards of signalling & interlocking shall be complying with the requirements of the
Signal Engineering Manual.
5.8
Siding and trap points:
5.8.1 Siding shall be arranged in such a manner that shunting operations upon them shall
involve the least possible use of, or obstruction, to running lines.
5.8.2 Trap points shall be provided upon goods lines & sidings at their junctions with
passenger lines, with points normally set against the passenger lines and interlocked with the
signals.
5.8.3 Bay and loop platforms line & refuge loops shall be isolated from main through lines.
5.9
Junctions of tracks: bars or other appropriate devices shall be provided in order to
define the fouling points of junctions, loops, siding connections, crossings and the like.
5.10
Isolation at stations:
5.10.1 The speed of trains running through stations shall be governed by the General Rules for
all open lines administered by the railway administration, both government and non-government
railways and shall be subject also to the restrictions relating to the standards of Interlocking in
the Signal Engineering Manual.
5.10.2 At no station at which isolation has not been provided, through running trains shall not
be permitted at speed 50 Kilometre per hour or less, unless all shunting has been stopped and no
vehicle unattached to an engine or got properly secured by the Station Master, in accordance
with provision of special instructions, kept standing on connected line which is not isolated from
the through line.
5.10.3 At any station where there is a speed restriction for through running trains different
from neighbouring stations, speed restriction board should be erected at the first approach signal
or where no signals are provided, at full braking distance outside the first facing point.
5.10.4 In order to maintain safety for through running, points for trap siding must not be
inserted in the main line or through line, except under approved special instructions in
102
accordance with the Signal Engineering Manual Part-I.
5.10.5 All the passenger running lines may be isolated from all sidings connected thereto.
5.10.6 All goods running lines may be isolated from all siding connected thereto.
5.10.7 It is not necessary to isolate one goods receiving line from another.
5.10.8 Isolation may be accomplished by:
a) Connection to another line or long siding,
b) The provision of short dead end siding,
c) The provision of trap.
Which ever may be the method for isolation, a starter signal shall be provided except when
allowed to be omitted under special approved instructions and when a trap is provided for
isolation the trap switch should be located with the heel of the switch in rear of the fouling mark
and preferably on straight. The switch shall be in the rail away from the line to be protected.
5.10.9 The various methods of isolation are:
Method A: Cases in which the line, on which the train will run when points are set for isolation
of the through line, is kept clear for the adequate distance, which shall be 180 metres at stations
equipped with two aspect lower quadrant or two aspect colour light signals and 120 metres in
case of station provided with multiple aspect signals or modified lower quadrant signals.
Method B: When a short dead end siding is provided, it shall not ordinarily be long enough to
permit of vehicles being stabled thereon. To obtain the adequate distance prescribed as
mentioned in method A above, the points of the dead end siding shall be set for the cross over
and against siding, before a train is admitted on a line trapped by this method. Where it is
necessary for the dead end siding to be extended for the purpose of stabling vehicles, the above
rule shall apply, unless a trap is provided on the dead end siding at a distance of not less than
180 metres (120metres in case of station provided with multi- aspect signalling) from the starter
signal where provided or from points leading to the main or through line. No train must be
admitted on the running line unless the trap is set and locked against vehicles occupying the
further part of the dead end siding.
Method C: When a trap is used, a train must not be admitted on to the trapped line unless the
trap has been closed, so that the train will not be derailed if the Loco Pilot overshoots the trap.
5.10.10 When Method A cannot be used, and for any reason it s not convenient to use Method B
or Method C and to provide adequate distance by setting the points of the short dead end siding
or trap for the crossover and against the siding or the trap, a sand hump of the appropriate design
should be used as a substitute for adequate distance as provided in rule 3.40(4) of General Rule
book. In that case the length of the siding should be at least one rail length and formation should
be made up for a short distance beyond the sand hump.
5.11
Summary: It is hazardous for a train running through a station at any speed if any
vehicle standing loose on an adjoining line may roll though and infringe upon the line through
which the train is scheduled to run through. To safeguard against such a situation to arise, the
problem is categorised in two parts one for stations where trains are allowed to run-through at a
103
speed of 50 kilometres per hour and other where the trains are allowed to run through at a speed
above 50 kilometres per hour.
At stations where trains are allowed to run through at a speed of 50 kilometres per hour or less,
though isolation is not required but it has to be ensured that the vehicles on adjoining lines
connected with the line on which the train is to run-through, are either attached with a loco or
are secured or fastened with track in such a way that they do not roll due to any reason be it
vibration of the running train or gradient.
At stations where the trains are allowed to run through at a speed of more than 50 kilometres per
hour, the lines on which the train is scheduled to run through shall be isolated from all other
lines by one of the three Methods described as Method A, Method B and Method C as above.
In case of Method A, adequate distance beyond starter or the place at which the train is proposed
to stop shall be kept clear. The adequate distance shall be 180 metres in case of two aspect
signalling be it semaphore or Colour light and 120 metres be it case of multiple aspect
semaphore, modified lower quadrant or colour light signalling. See Fig. 5.7.5.a.
120 mts
120 mts
FM
Run through line
Run through line
Fig. 5.7.5 (b-I)
Method B for isolation with short siding
Fig. 5.7.5 a
Method A for isolation
In case of Method B, a short siding shall be provided ahead of the starter signal or the place at
which the train is proposed to stop. The clear length of the siding shall be the prescribed
adequate distance as discussed in method A above. This siding shall under no circumstances be
used for shunting or stabling of any vehicles. A long siding may also be provided instead of
short siding, however a trap point shall be provided at an adequate distance beyond the starter or
at which the train is proposed to stop, here the length upto trap shall invariably be kept clear.
However in exigencies when the siding is obstructed for any reason the adequate distance shall
be deemed not to be available. See Fig. 5.7.5 (b-I) & Fig 5.7.5 (b-II).
120 mts
Run through line
Run through line
Fig. 5.7.5 (b-II)
Method B for isolation with longer
siding & a trap
Fig. 5.7.5 c
Method C for isolation with a trap
104
In case of Method C, A trap point shall be used for the isolation purpose, which shall be kept
open to isolated main line, through which the train has to pass, from loop line to be isolated.
However in such case while receiving the train on loop line, the trap must be closed to set
overlap towards the run-through line. See fig. 5.7.5 c
In case none of the methods is feasible for any reason a sand hump of approved design shall be
provided which is considered to be an adequate replacement of short siding, long siding or tarp
point. The sand hump shall be connected with the track keeping at least one rail length in
between. See Fig. 5.7.5 d
Further more, all passenger running
lines shall be isolated from all goods
lines or sidings; all goods running lines
shall be isolated from all sidings and it
is not necessary to isolate goods
receiving lines from each other.
Sand hump
Run through line
fig. 5.7.5 d
Isolation with a sand hump
5.12
General:
5.12.1 The requirement and regulation of Block Instruments shall be in accordance with
section “N” and section “R” of chapter VII of the Signal Engineering Manual, Part – I.
5.12.2 The requirement of Centralised Traffic Control (CTC) shall be in accordance with
section `Q’ of chapter VII of the Signal Engineering Manual, Part – I.
5.13
Catechism for signalling and Interlocking installation: One of the methods to verify
that the all requirements pertaining to the work have been fulfilled, the best is catechism, which
is listing out questions, answers to which not only verifies the part of the work done but also
reminds of the lapses if any. Interestingly some of the questions provide information otherwise
not available elsewhere.
5.13.1 Inspection at the Signals:
i)
Are all running signals controlling trains placed in such a height above rail level so that
they can be clearly seen by Loco Pilots in sufficient time and be readily distinguished by
night or by day from the subsidiary signals?
ii)
Are all signals constructed so that their normal position is at Òn’ or most restrictive and
that they stand at or return to this position in case of failure of any part of the signals or
their connections except in case of Automatic signals, the normal aspect of which is
Òff’?
iii)
Do all signals come fully Òff’ when worked and return freely to the Òn’ position?
iv)
In case of slotted or controlled signals, can the signals be freely returned to danger by
either of controlling agencies except in case of signals controlled by key transmitter or
any such control?
v)
Are signal counterweights, where possible, fixed out of reach?
vi)
Is the facing side of the arm of the semaphore signals, including miniature and disk
signals, but except Calling on signals, painted the same colour as the light exhibited in
the Òn’ position?
105
vii)
viii)
Are signals not in use fixed at Òn’ and distinguished by having to crossed bars attached
to them, each bar being not less than one metre long and 100 millimetres wide?
Are all signals of standard type and do they comply with the requirements as laid down
in the General Rules and have they been passed by Sighting committee?
Whenever a new signal is installed or the position of an existing signal is changed, the
signal is required to be passed by a Sighting Committee consisting of a Loco Inspector,
Section Engineer (Signal) and Traffic inspector, before the signal an be brought in use.
ix)
x)
xi)
xii)
xiii)
xiv)
xv)
xvi)
xvii)
xviii)
xix)
xx)
xxi)
xxii)
xxiii)
Are all fixed signals, the front light of which cannot be seen from the point from which
they are worked, provided with a small white backlight not larger than is actually
necessary and visible only when the signal is at Òn’? Also is the fixed green light of
every Warner, which is used by it, provided with a white back light?
Do all the Distant signals in Multiple Aspect area show two back lights in Òn’ position
and no light in any other position or where electric lighting of Distant signals is
provided, it shows at least on back light in the Òn’ position? However colour light
signals shall not be provided with back light since these are provided with visual
indication.
Do miniature and dwarf signals, used to control shunting show the same front and back
lights, as are prescribed for running signals and are the lenses small enough to make
them distinguishable from running signals?
Are signal lamp brackets fixed on the posts, and is suitable provision made for lighting
and cleaning lamps?
If any signal is placed at more than 180 metres away from the facing points it controls,
is arrangement made to keep the points locked until the train has passed them?
Are all signal arms placed on the left-hand side of the post as seen by the Loco Pilot of
the approaching trains to which the signals refer?
Are all signal posts placed on the left-hand side of the track of the approaching trains to
which they refer? If placed otherwise, for what reason?
Where two or more lines diverge, are signals fixed on a bracket post or on separate doll
post carried on Signal Bridge?
Where two or more lines converge, are signals fixed on altogether separate posts or
separate doll posts carried on single bridge?
Are bracket and the bridge signals arranged so that each signal from left to right, from
the point of view of approaching trains, applies to each corresponding line from left to
right, and are they distinguished by grouping and by marking the more important signal
higher to those of lesser importance? Here the highest signal must always refer to the
straight line.
In case of two or more signals referring to parallel lines, are they arranged in transverse
line as nearly as circumstances allow?
Does any case occur or more than one signal referring moving in the same direction
being placed on the same post, other than Warner, shunt or calling-on signals?
Are Warner signals fixed 1.5 to 2 metres below stop arm or fixed green light?
Are Co-acting or Calling on signals placed not less than 2.5 metres below the
Semaphore arm above?
Are Warner signals, which are un-worked, secured in the Òn’ position?
106
Are arrangements made to render it impossible for the Warner arm to be taken Òff’
independently of the stop signal arm above it and when the stop signal arm returns to
danger, the Warner if Òff’ automatically returns to danger?
xxv) At diverging junctions, is one Warner signal only provided applying to the through line?
xxvi) Do all signal lights show red in the Òn’ position, or yellow/double yellow in the case of
Distant signals, or no light in the case of Calling on signals?
xxvii) Do all running signal lights show green in the Òff’ position in two aspect signalling
sections and yellow, double yellow/green in multiple aspect signalling section?
xxviii) Are signals where necessary effectively guyed?
xxiv)
5.13.2 Inspection at points:
i)
Is the locking of facing points is such that points can not be or become unlocked while a
train is passing over them? i.e. a) are lock bars provided of a length exceeding the
greatest distance between any two adjacent axles likely to be used on the line or
alternatively is the point or lock lever electrically controlled by the track circuits? b) In
case of key locks, are the locks either under the train and therefore inaccessible or if not
placed under the train, is the arrangement such that the key is used to release the signals
and that it cannot be brought back to the points until such signals have been up to the
Òn’ position?
ii)
Is the arrangement such that the operation of the facing point lock depends on the
correct operation of the lock bar where used, and it is impossible for the lock bar to be
forced over while a train is passing over it?
iii)
Are the locks of a substantial pattern and make? Are they fixed in such a manner as to
ensure the necessary rigidity and are key sufficiently large and strong to minimise the
chance of their being mislaid or broken?
iv)
Do key locks fitted to facing punts on the passenger running lines lock both switches?
v)
Are the switches adjusted to come tight against stock rails? Does the insertion of 5 mm
obstruction piece between the switch rail and the stock rail, 150 mm from the toe of the
switch prevent the points being locked and prevent the relevant signals from being taken
Òff’, the giving of which is preceded by the locking of the points?
vi)
Do facing point plungers clear the stretcher bar blade when the points are unlocked and
in the event of there being an obstruction at the points, it is impossible for the point lock
plunger to enter the stretcher bar blade and for point lock lever to be forced into its
normal or reverse position?
vii)
Are all facing points fitted with a gauge tie plate where steel sleepers are not provided at
the toe of switches, and are they provided with split stretcher bars or other fitting giving
equal security?
viii)
Are all points, locks and detectors securely fixed?
ix)
Are detectors fitted to all facing points and do they efficiently detect with both switches,
the signals controlling the movement of the trains over them?
x)
Are trailing points on passenger running lines used in the facing direction for shunting
movements which are not fitted with facing locks, detected with the relative shunt
signals?
xi)
Is it possible for any detector slide to enter a notch other than that intended for it?
107
xii)
xiii)
Do point indicators show the prescribed indications i.e. white for the straight green for
the turnout in both directions and where fitted to trap points red in both directions when
trap is open and green in both directions when trap is closed?
Where point indicators of the directional type have been provided has this been done
under approved special instructions?
5.13.3 Inspection on the track:
i)
Are all through lines isolated from each other, from other running lines and from all
sidings?
ii)
Are running lines isolated from all sidings and goods lines, either by a) trapping into
dead ends taking off the sidings or goods lines?
iii)
Are dead ends traps so locked as to prevent any possibility of the running lines being
fouled for which signals have been taken ‘Off’?
iv)
Are dead ends traps fitted with indicators, or they are protected by signals?
v)
Are dead ends and traps placed in such a position as to ensure that any vehicle that may
be derailed by them shall not foul any running line?
vi)
a) Are all points worked by rodding within a distance of 320 metres from the lever
operating them?, b) if the distances are greater than those specified in (a) , are they
within the limit of 460 metres , and is a stroke of not less than 200 mm provided at the
lever tails?
vii)
Is the rodding efficiently laid and properly compensated where necessary, and means of
adjustment provided?
viii)
Are all signal connections efficiently installed and means of adjustment provided?
5.13.4 Inspection of the cabin or at the lever frame where there is no cabin:
i)
Is signal cabin provided with the following essentials:
a) A clock in cabins where train movements are registered.
b) A diagram correctly representing the arrangement of the points and signals worked
from the cabin in their normal position and the number of the points and signals?
c) Lights so arranged as not to be mistaken for running signals or interfere with their
sighting?
ii)
Is there sufficient space in the cabin to allow the man or operator freedom of movements
for manipulating the levers or other apparatus in the cabin?
iii)
Is the gear leading off from the cabin or frames securely fixed?
iv)
Are the levers painted with distinguishing colours and in addition to its own number
does each bear the numbers of the levers, which must precede it, and in the proper
order?
v)
Is the cabin so located and built as to enable the cabin man to have the best possible
view of all the points and signals, the working of which he is responsible for and also,
for all movements under his control?
vi)
Are all signals, which are not visible from the cabin or frame electrically repeated? If so,
does the repeater repeat the light as well as the arm?
vii)
Have instructions for working have been issued to the staff and included in the Railway
Working instructions, and are they correct and sufficient?
viii)
Is the Station Master provided with interlocked mechanical or electrical control of the
Home and Last Stop Signals?
108
5.13.5 Test to be made in the lever cabin or at the Lever frame: It is essential that the
interlocking of all signals with the points is so effected as to ensure the following conditions,
which may be tested from the cabin or frame by pulling over the levers for each combination
allowed by the locking table and checking the security of each such combination by attempting
to infringe it:
i)
ii)
iii)
iv)
v)
vi)
vii)
viii)
ix)
Is it possible to take ‘Off’ conflicting signals at the same time?
Is it possible to take Òff’ signal until a) all points on the running line including overlap
are correctly set and the facing points locked? b) All points giving access to running line
from sidings and goods lines, are set against the running line? c) Level Crossing gates, if
included in or controlled by the interlocking, are locked across the roadway?
A signal lever, when operated , locks or back locks as necessary, the levers operating the
points and gate locks referred to in this paragraph?
When all signals are Òn’ are all points, which would be locked by the taking Òff’ such
signals, free for shunting purposes?
Is it possible to take Òff’ a Warner signal until all the relative stop signals in advance
have first been taken Òff’ and when Òff’ does it back lock such signals?
Does the locking in the frame correspond with that shown in the approved locking
table?
Is the locking strong, durable and accurate, i.e. can any tappet enter a notch other than
for which it s intended, or can the locking be forced?
Does the locking in the lever frame act on the commencement of the movement of the
lever in case of direct locking type of lever frames and on pressing the catch handle in
case of catch handle/ Double Wire type of lever frames?
Is release locking not effective before the completion of the movement of the lever?
5.13.6 Power operated points and signals: These questions are to be read in addition to the
questions for other signalling and interlocking installations to the extent they are applicable to
power operated points and signals:
A.
i)
ii)
iii)
iv)
v)
vi)
B
i)
Signals:
Is the mechanism case weather proof and protected for unauthorised interference?
Do the indication contacts close if the arm is more than +5 or - 5 degrees from Òn’ or
Òff’ Position?
Is the signal and hold off mechanism so constructed, that in the event of a failure the
signal shall go to the Òn’ position?
With the exception of motor commutators, etc is a surface leakage distance of not less
than 6mm provided between any exposed metallic part of the mechanism carrying
current and other metallic part thereof?
Are the signals so bright as to cause confusion in reading at night?
Does the signal give distinct indication to the Loco Pilots when approaching or stopped
at a signal?
Points:
Is the switch operating mechanism of substantial design securely fixed and protected
from unauthorised interference?
109
ii)
iii)
iv)
v)
vi)
vii)
viii)
C.
i)
ii)
iii)
iv)
v)
vi)
vii)
D.
i)
ii)
Is the mechanism provided with means for emergency operation in the event of a
failure?
Does the use of the bank or other apparatus for emergency operation disconnect the
power supply to the motor and prevent clearance of the signal for such points are
required to be set?
With the exception of motor commutators, is a surface leakage distance of not less than
6mm provided between any exposed metallic part carrying current and other metallic
part of the mechanism?
Is the mechanism so constructed that it can be stopped revered or obstructed at any point
of its movement without damage?
Is the mechanism so constructed that it cannot give a `Normal’ or `Reverse’ indication,
unless the closed switch be within 5 mm of the stock rail and in the case of facing
points, switches are properly locked?
In order to prevent the movement of points while a train is passing over them, are facing
points provided with lock bar, alternatively with track circuit locking of the point lever?
Where the movement of trains over the points are not within easy visibility of the cabin,
is occupation of the section between the stop signals leading to over the points and the
fouling point ahead of such points, electrically indicated in the cabin?
Cabin and Lever Frame:
In the case of power interlocking frames, is the lever frame mechanism completely
enclosed with removable covers giving free access to all parts and provision made for
securing such cover against unauthorised opening?
Are all exposed metallic parts carrying current, not less than 6 mm surface leakage
distance between and any other metallic parts of the mechanism?
Are the levers operating power worked points provided with `Normal’ and `Reverse’
indication locks, adapted directly to prevent the full the movement of the lever, unless
the point mechanism has made the required movement and the point is in a position
corresponding to that of the lever and in case of facing points, unless the point is
securely locked? This test shall not be required where alternative electrical locking is
provided.
Are the levers operating power worked signals provided with `Normal’ indication locks,
adapted directly to prevent the full return movement of the normal, unless the arm has
returned to the Òn’ position? This test shall not apply to a mechanical lever frame, if
the signal is repeated at the place of operation through an arm and light repeater.
Are all electric locks mechanically replaced to the locking position?
Is all the wiring between different parts of the apparatus made with suitably insulated
wire and efficiently protected?
Is the lever frame properly earthed and are efficient safeguards provided to prevent
injury to the operator, in the event of a short circuit or other similar circumstances?
Cables and circuits:
Do all main cables terminate in properly sealed boxes?
Are circuits controlling the operating and indication of signals so arranged that as far as
practicable a cross connection or a short circuit on any of the wires, cannot give a false
`Clear’ indication?
110
iii)
iv)
v)
vi)
vii)
viii)
Are circuits controlling the operation and indication of points arranged such that, as far
as practicable, a cross connection or short circuit cannot operate the switch or give a
false indication of the position of the points?
Is the battery or power supply for line circuits, as far as practicable, arranged at the end
of the circuit farthest from the operated unit?
a) Are all main track circuits as far as practicable so arranged as to provide the best
protection against broken rails, points crossings etc? b) Are the adjacent track circuits
staggered in polarity?
Are sidings and junctions track circuited upto the fouling mark?
Are hand worked switches in or leading to automatic signalling territory, equipped with
a circuit controller operated by the normally closed switch?
Are such switches electrically locked by the approaching track circuits to prevent their
movement in the face of an approaching train?
5.13.7 Signalling and Telecommunication installation in 25 KV 50 Hz single conductor
AC electrified sections:
A.
Signals:
i)
Are the signals located in accordance with the approved Instructions as per Manual of
instructions for installation of Signalling and Telecommunication Equipment in 25KV,
50Hz AC electrified section?
ii)
Have the protective iron screens as required for signals/fittings within 2 metres of live
conductors / parts been provided and earthed?
iii)
Where it is not possible to provide protective iron screens, has a caution board been
provided on the signal posts in accordance with the approved instructions?
iv)
Has the `Signal Sighting Committee’ certified that the Loco Pilot’s view of the signal is
clear?
v)
Have only multi aspect signals been used in colour light signalling area?
vi)
Is the AC power supply arrangement for the colour light signals of a type approved for
Railway Electrification areas?
B.
Points:
Have the rodding transmission of points and other apparatus been insulated as per the
approved instructions?
C.
i)
Electrical Signalling equipment:
Does the design of Signalling equipment and the circuit used in Railway Electrified
areas provide for safety factor 1.5 against AC interference?
Has it been ensured that the signalling equipment not suitable for Railway Electrified
areas on external circuits like banner type indicators, Luminous indicators, Telephone
type relays, Electrical Lever locks, rotary key transmitters, DC neutral polar relays of
250 ohms, DC neutral line relays and door coils of IRS block Instrument etc have not
been used?
Has it been ensured that all stick relays have at least 4 front and 4 back contacts and
their pickup transfer time is not less than 300 milliseconds?
ii)
iii)
111
D.
i)
ii)
E.
i)
ii)
F.
i)
ii)
iii)
iv)
G.
i)
ii)
iii)
iv)
v)
Cabling and wiring circuits:
Have all telephone circuits, except cabin to cabin to ASM circuits, which may be
retained on signalling cable, been transferred to separate underground
telecommunication cable?
Have all overhead wire circuits been shifted or cabled as per the approved instructions?
a) Has it been checked that the voltage induced due to parallelism in the
telecommunication cable under normal and short circuit conditions are within safe
limits as specified by the consulting Committee of International Telegraph and
Telephones?
b) Has it been ensured that the earth return circuits are not retained and have been
replaced by metallic return circuits except block circuits?
c) Has the principle of double cutting been used isolated for internal circuits and
batteries?
d) Has the external circuits and batteries been isolated from internal circuits and
batteries?
e) Has it been ensured that the induced voltages in the length of inter-cabin telephone
circuits in signalling cables does not exceed 60V?
Batteries:
Has it been ensured that power supply for internal and external circuits and for each
block instrument are isolated?
Has it been ensured that the battery for signalling equipment is separate from the battery
for telecommunication equipment?
Earthing:
Have the lever frames and other equipment been earthed in accordance with the
approved instructions?
Has it been checked that no earthing pipe is less than 3 metres away from any other
earthing pipe?
Has it been tested that the earth resistance does not exceed 10 ohms for the signalling
equipment and 1 ohm for telecommunication copper cable earth?
Has the screening of the telecommunication cable terminated at the sectionalising points
and repeater stations been earthed in accordance with approved instructions?
Track circuits:
Has it been ensured that track circuits are of approved type?
Have measurements of DC stray currents been taken before installation of DC single rail
track circuits and whether these are within permissible limits?
Has the longitudinal and transverse bonding in track circuited areas been provided as per
the approved instructions?
Have the DC single rail track circuits of closed type been installed in accordance with
the approved instructions?
Have the protective measures like surge dischargers (Interval of Discharge) been
provided on track circuits, where required as per the approved instructions?
112
H.
i)
ii)
iii)
iv)
v)
vi)
vii)
viii)
ix)
x)
Block Instruments:
Are the block instruments installed of a type approved for the use in AC electrified
sections?
Have block filters for single line and double line block instruments been provided in
accordance with the approved instructions?
Are the filter units of an approved design?
Have the line terminals of block filters been painted red to caution the maintenance staff
against high voltage?
Where a block section falls between an electrified and non electrified section, has it
been ensured that bock filters have been provided for block instruments at either ends of
such block sections?
Have the block telephones been provided on a separate pair of conductors in accordance
with the approved instructions?
Have the block circuits been provided on underground cables as per the approved
instructions.
Have three position polarised relays of SGE block instruments been provided in
accordance with the approved instructions?
Have the block release and Advanced starter control of block instrument been provided
in accordance with the approved circuit?
Has it been ensured that the circuits from a non-electrified section approaching an
electrified section and vice versa been cabled for a length of 1 kilometre beyond
electrified sections?
*****
113
Chapter IV Self Assessment
1
2
3
4
5
The amount granted against capital fund is
financed by Central Government only when
rate of return is:
a) 14% or more*
b) 13%
c) Both a) & b)
d) None of above
The tender received after the scheduled time
of opening, are:
a) Delayed tender
b) Late tender*
c) Normal tender
d) All of above
In two packet system, the tender document is
divided into:
a) Credential bid
b) Financial bid
c) Only a)
d) Both a) & b)*
Termination Indicator shall be provided for:
a) Passenger train
b) Goods train
c) Both a) & b) are correct*
d) Only b) is correct
Demand No.16 is meant for:
a) Revenue receipts
b) Capital expenditure*
c) Revenue expenditure
d) Development expenditure
6
The cost of work to be tendered includes the cost
of material:
a) To be supplied by Railways
b) To be supplied by contractor*
c) To be supplied by both Rly &contractor
d) To be supplied by sub contractor
7
Various methods of providing isolation are:
a) Sand hump
b) Track circuits
c) Long or short siding
d) Any one of the above*
8
Catechisms for installation is:
a) Requirement of the work before
commissioning
b) Listing of questions
c) Check list in the form of questions*
d) None of above
9
In case of execution of signalling work on
running lines, the copy of safety certificate
issued by Engineer shall be given to:
a) Commissioner of Railway Safety
b) Divisional Railway Manager
c) Chief Signal & Telecomm Engineer
d) All of above*
10 The size of cross to be provided on new signals
before they are brought into use, shall be:
a) One meter x 200 mm*
b) 1.2 meter x 200 mm
c) One meter x 250 mm
d) 1.2 meter x 250 mm
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Construction organisations are headed by General Manager also. True*/False
For expenditure against judicial awards, parliament’s sanction is required. True/False*
The DOC extension may also be granted on account of lapses on contractor’s side. True*/False
Caution indicator shall be mounted at the height of 2 meters form the rail level. True*/False
Delayed tenders can be considered for award of work under normal circumstances. True/False*
Last accepted rates & SOR both are one and the same thing. True/False*
It is not essential to inform the contractor against whom risk & cost tender is being floated. True/False*
Late tenders can not be considered for award of work under normal circumstances. True*/False
The agreement shall be signal by the same officer who accepts the tender. True/False*
Whenever a work, which is not there in contract, is essentially required to be done to progress the main
work in contract, it can be executed pending sanction of the accepting authority in view of emergency.
True/False*
114
1.
2.
3.
4.
5.
Describe briefly procedure for execution of work starting with the stage of allotment of tenders for the
work.
Give the format for issue of telegram bringing the work into use. At what stage the concerned Engineer
incharge shall issue the safety certificate if CRS has proposed not to inspect the work before
commissioning, while according his sanction.
Prepare rate analysis for casting of one foundation for colour light signal. The specifications,
parameters & rates of various items may be assumed realistically.
While you are a member of tender committee, how would you proceed. Give step by step and elucidate
the important factors which you shall keep in account while drawing T.C. minutes.
A variation in the contracted values takes place during the course of execution of work. Please detail
the process for regularising it.
*****
115
CHAPTER – V
RAILWAY ACCIDENTS
1
i)
ii)
iii)
iv)
v)
vi)
Categories of train accidents: Train accidents may be categorised in:
Derailments,
Collisions,
Accident at Level crossing,
Parting of train,
Incomplete arrival of train.
Vehicles escaping from the station.
1.1
i)
ii)
iii)
iv)
v)
vi)
vii)
viii)
ix)
x)
xi)
xii)
Different causes of these accidents may be attributed to:
Failure of station staff,
Failure of Loco Pilot,
Failure of technical staff,
Track defects,
Vehicle defects,
Signalling & Interlocking defects,
Other Human failure,
Ruthless Driving by road vehicle drivers,
Short circuiting in the wiring of coaches,
Carriage of inflammable materials,
Anti-social elements causing fires,
Sabotage.
A decade wise trend of accidents in these categories are tabulated as below*. This table is an
indicator of decreasing trend of accidents:
Years
Number of Accidents Million train
Incidence of train
(Yearly Average)
Kilometres (Yearly
accidents per
Average)
million train Kms.
(yearly average)
1960s (1961-1970)
1393
433.8
3.3
1970s(1971- 1980)
866
480.9
1.8
1980s (1981- 1990)
757
559.8
1.4
1990s (1991- 2000)
464
655.8
0.7
2000- 2003 (av)
412
686.6
0.6
2002 – 2003 only
349
793.8
0.44
2
Intimation of accident: The Loco Pilot or the Assistant Loco Pilot or the Guard of the
train involved or any other train passing by or by nearest gate man or by any other means, the
section control shall get the information through Emergency control circuit of the details of the
accident occurred in the Block Section. In case of accident takes place in the station section, the
-------------------------------------------------------------------------------------------------------------------* Extract from Indian Railway Safety by Arya Bhushan & M.M. Agarwal.
116
Station Master on duty, who shall come to know of the accident first shall inform the Section
Controller.
It is the Test room, situated near the complex where Chief Controller and the Section
Controllers are placed, are first to come to know about the incidence for S&T Organisation. The
Senior Section Engineer In-charge shall collect the information of site, time, trains involved,
casualty if any, extent of damage to the track and S&T equipment. He shall inform S&T
officers, SSE, SE JE and other artisan staff to reach the site.
A hooter is sounded at the Divisional headquarters station yard to intimate the concerned
railway staff to reach the site of accident. The hooter codes also gives vital information about the
accident.
3.
Accident Relief Train (ART): A train equipped with Tools plants, crane,
communication arrangements, coaches to carry staff and officers, medical van, Spares of general
nature for S&T and other departments is kept ready to move on short notice to the site of
accident, at the divisional headquarters and at such places where the train can be accommodated
and shall be able to cover reach of entire division taking minimum time.
The ART is inspected by Officers frequently to ensure all tools, equipment and spares are
maintained in fit to use condition.
4.
Post accident action:
4.1
It is the prime responsibility of each railway officer and the employee associated with
the maintenance of the section, to reach to the site of accident as quickly as possible
immediately after getting information of the accident. The Senior most Officer or senior
subordinate travelling in the affected train whether on duty or on leave and whether or not
associated with the section in which the accident takes place shall take charge of the situation till
an officer associated with the section reaches the site, and arrange for rescue of the passenger
without disturbing the evidence of the accident.
4.2
The officer in charge shall arrange for joint investigations and recording the
measurements, a sketch, statements of the station and train crew and other staff concerned with
the accident and other vital information to be carried out by Senior subordinates of traffic,
Loco/ electric (operation), Civil engineering (P. Way) and of a branch apparently not concerned
with the accident.
4.3
He shall arrange simultaneously placement of ART, Establishment of communication
with the divisional headquarters other measures for restoration of traffic.
4.4
Action shall be taken to:
4.4.1 Rescue the passengers, arrange first aid to injured and sending them to nearest
hospital. All passengers stagnated with the train shall be sent forth to their normal
journey as soon as possible.
117
4.4.2 Communication shall be established by S&T department i) between site of accident and
divisional headquarters using emergency control circuit or administrative line connected through
emergency sockets or using BSNL, GSM(Rly.), satellite link or any other service provider and
ii) between work force and officers at site of accident using VHF system.
4.4.3 Enquiry into cause of accident: One of the important action to be taken after the
accident is to establish the cause of the accident so that remedial measures may be taken to
prevent repetition. For this:
i)
Take measurements, photographs and carryout other observations, prepare a sketch and
other measures to preserve evidence in bringing out cause of accident.
ii)
Take statements of staff relevant to the accident and who could be helpful in
establishing the cause of accidents.
iii)
Prepare a preliminary enquiry report jointly by senior subordinates. This shall be done
as quickly as possible as the restoration work shall start only after completion of this
activity.
iv)
It shall also be ensured by all Officers and Senior subordinates available at site of
accident that a) no evidence is tempered, dislocated or shifted, while at the same time b)
no evidence is omitted from being put on record howsoever insignificant it may appear
to be.
4.4.4 While enquiring into cause of accident the senior subordinates of Traffic, Signalling, P.
Way and any other branch of railways who may be concerned with the cause of accident, shall
take all actions such as taking statements, measurement s etc, jointly.
4.4.5 Restoration of normal traffic shall be done as quickly as possible.
5.
Derailments:
5.1
In Block Section: In normal course there is no involvement of S&T department if train
derails in Block section except for assistance in restoration of traffic by way of providing
communication.
5.2
In Station section: train may derail in station section on i) the point, due to a gap
between switch rail and stock rail. This situation is called no road. ii) points moving in face of
the approaching train, when the point is neither set normal nor reverse, in this case also no road
situation shall arise, iii) points moving under the wheel, in such a situation some of the wheels
shall move on road set for one direction and other on the road set for other direction, iv) on
straight route where involvement of point is ruled out.
5.2.1 It is only in case of signalled movements where the interlocking system takes care of the
safety of the trains. In case of signalled move, the point is supposed to be properly set and
locked at site as well as in the interlocking. Possible reasons may be:
i)
Mounting or wedging through of any wheel of the train: The wheel flange shall not
be able to wedge through a gap of 5 mm or less between switch rail and stock rail of the
point. In a situation of such a signalled move where the wheel has been able to wedge
through the point, a no road situation shall arise. It also may happen that effort is made
to unlock the point immediately after passing the signal by the Loco, which may result
in riding of the wheel over the raised lock bar resting on the upper crest of the radial
118
ii)
guide. Under such circumstances it becomes the responsibility of S&T to clear its
position.
Points moving in face of the approaching train: In case of change in decision to
receive the train on a line other than for which signals had been taken ‘Off’ after the
Loco Pilot accepts the signal. If the reception signal is put back, the point unlocked and
changed but the driver is not in position to bring his train to a stop before the reception
signal, he is likely to encounter the points moving, resulting in no-road and as such
derailment. In such a situation a controversy shall arise as the Loco Pilot shall be telling
that he saw signal Òff’ while approaching the same and then saw signal going back to
Òn’ but the station staff shall be telling that the signal was Òn’ only. The lever
position in the cabin shall also support the operating staff‘s version. However it can be
established if the Station Master’s log register record is upto-date and the section
Controller‘s statement supports the change in decision. This can also be established if
the data logger is provided at the station and is functioning well. In this case chances of
damage to switch or stock rails are negligible except because of drag after derailment.
fig.5.2.3
Derailment when points are in no road condition.
iii)
Points moving under the wheel: situation is not possible in case of signalled
movement. In case of rod operated points it may be possible if the lock bar is not
effective and it is possible to move the lock bar under the wheels. Lock bar may
become non-effective if out of 12 lock bar clips at least three in a row were lying
unbolted and not supporting the lock bar thereby reducing the effective length of the
lock bar. However if the track locking is achieved through track circuits, the movement
of points may take place only due to equipment failure or unauthorised interference. In
this case chances of damage to switch or stock rails are negligible except because of
drag after derailment.
iv)
Investigation:
a) Seizure of records: All records with the train movement in the Station Master’s
office, both the cabins and Loco Pilot shall be seized.
b) Statements: statement of Station Master, cabin Masters of both the cabins and Loco
Pilot/ Assistant Loco Pilot shall be taken,
c) Inspection & tests:
i) If the switch rail area of the point is not damaged the point should be tested with
obstruction piece of 5 mm in between stock and switch rail to see if the point
gets locked in the position on which derailment took place. It is important to
note that if switch rail toe area is damaged due to accident, obstruction test
should not be resorted to as it becomes very difficult to establish the integrity of
119
the locking arrangement if the toe area of the switch rail is damaged due to
derailment. Sharp wheel flange, is able to wedge through the switch rail or
mount the switch rail, as such in either case first wheel derailed should be
checked for sharp flange. A wheel flange thinner than 22 mm measured from
wheel gauge face at 13mm from outer edge of the flange, is not permitted to be
used on high speed trains (IR Safety, by Arya Bhushan and M.M. Agarwal).
The shape of a sharp wheel flange is shown in the Fig 5.2.1.
ii) Uneven loaded goods vehicle or shifting of load is also responsible for wheel
jumping off the rails.
iii) There have been cases of wheel mounting on the toe of switch rail giving false
indication of gap in the switch and stock rail also mounting on heel block. Both
the situations become complicated because of damages due to derailment.
In all the three situations other than derailment on
straight route, wheel marks should be located and
recorded through sketch also. In case of wheel
mounting at heel block there shall be clear dent marks
on the inside fishplate joining wing rail and switch rail.
In case the wheel flange has mounted on toe of the
switch rail clear longitudinal dent shall be observed on
the toe of the switch. However this should be
distinguished with normal wear on the toe of the switch
rail formed over the period due to tight gauge or due to
Fig.5.2.1
curvature. The marks of mounting of the wheel shall be
profile of the wheel flange
deep while wear marks shall be in the form of
shown in firm line and
longitudinal scratches. In case the wheel flange wedges
sharp , in dotted line
in between switch rail and stock rail at the toe of the
switch there shall be light scratch marks inside the switch rail at the toe of the switch,
besides there shall be scratches on the stock rail also at the same place as on switch rail,
facing point lock (FPL) may get shifted and might even shear off the holding bolts of
the FPL. In case of electric point machine also the point machine may get shifted, or
bolts holding point machine may get sheared off or base of the point machine may get
broken at the hole meant for holding bolts. Point machine should be opened after
verifying integrity of its locking arrangement to check for status of point locking
assembly. Any one of the observations shall be suggestive of that the point adjustments
were as such that it could not have been possible to lock the point with 5 mm
obstruction in between stock and switch rails.
d) Preparing sketch: A sketch shall be prepared showing point of mounting of wheel
point of drop and drag along with other significant information.
5.2.2 Derailment on straight route: Derailment on straight route may take place because of
hanging brake block or any other part of vehicle falling in track, tight or slack gauge, rail
fracture during winter, track buckling during summer, uneven loading or shifting of load,
running over of animals etc.
120
6
Collisions: Collisions may be within station section or in Block section. It may be i)
Head-on collision, ii) Head to tail collision, and iii) Side collision.
6.1
Collision in station section: In station section any of the three types of collision may
occur.
6.1.1 Head-on or head to tail collisions: Any of the two may occur because of wrong
allocation of line or passing a signal at Òn’ by Loco Pilot. In extreme exigencies equipment
failure or unauthorised interference with the system may result in signal coming Òff’ for an
occupied line where flank protection is provided.
The yard may be equipped with i) no track circuiting of berthing track in the yard, ii) main line
track circuited between fouling mark to fouling mark where loop lines are not track circuited. iii)
entire yard track circuited.
i)
ii)
iii)
iv)
In fist case where no track circuiting of berthing track is available observing clearance
of line is to be done by the Station Master, manually. In such a case any laxity in
checking line clearance may result in head-on or head to tail collision. Another situation
may be where the Loco Pilot has passed the signal at Òn’. In both the situations it is
very difficult to find out the cause if the station staff takes a stand that the Loco Pilot has
passed the signal at Òn’ and the Loco Pilot says that he saw the signal Òff’. The
inference shall be drawn about the cause of accident by the Train Log records of the
Station Master and both the cabins along with their `private number’ books , if taken
into custody in time, the statements of the Operating staff of the station and the Loco
Pilot, Assistant Loco Pilot and the Guard of the affected train.
In second case where mainline is track circuited while loop lines are not track circuited,
the collision taking place on non track circuited line shall lead to a similar situation as in
first case. However in case the collision occurs on track circuited line it shall not be
possible to take Òff’ the signal for the occupied line and hence a train could not be
received on occupied line unless the track circuit had been bypassed. In this case also
inference can be drawn by observing the same procedure as in preceding paragraph (a),
except that in this case the signal failure book, presence of the signal maintainer at the
station with specific reference to the relay room should be given additional cognizance.
In case when the entire yard is track circuited usually in case of central panel
interlocking or RRI, The system is such that it is not possible to receive a train on a
track occupied besides unauthorised interference is almost impossible. The Central
panel Interlocked stations are usually provided with data-loggers which, when
accounted for with other records and statements of staff it is possible to a large extent to
substantiate the cause of accident.
Investigation:
a) Seizure of records: Train movement Log register, private number books of the
Station Master and both the cabins, Relay Room key register and Loco Pilots diary
of record should be seized under joint signatures.
b) Statements: Position of levers in both cabins and position of slides in SM’s slide
frame shall be recorded jointly. Statements of Station Master on duty, Cabin
Masters on duty of both cabins, Loco Pilot & Assistant Loco Pilot and the Guard of
121
the train, shall be recorded jointly. If the key of the relay room is found to be under
issue at the time of accident, the relay room shall be examined for any temporary
connections and observations put on record jointly. The data to establish time of
taking Òff’ relevant signals shall be retrieved in case data logger is provided at the
station. All information thus collected shall be analysed to establish the cause.
6.1.2 Side collision in station section: Side collision may take place in two situations, i) first
when a train is standing on a line infringing with the Schedule of Dimensions with the adjoining
line on a turnout or crossover and ii) the other case when coaches or wagons of derailed train
are fouling with the adjoining track. In this case when a train moves on the adjoining line
infringed upon, as mentioned, shall collide by its side with the other train.
i)
Side collision when the train is standing on a line infringing with the Schedule of
Dimensions with the adjoining line on a turnout or crossover: The GR4.56 provides
that `When a train comes to a stand at a station, the Guard shall see that, whenever
possible, the last vehicle of his train has cleared the fouling marks of all points and
crossings. If not, he shall inform the Station Master at once and exhibit Stop hand signal
to prevent any movement on the fouled line.’
In addition, on stations where point zone is not track circuited, a fouling bar is provided
linked with the point in such a way that it is not possible to change the position of the
point from the last operated position unless the train clears the fouling bar. With this it
shall not be possible to receive next train on adjoining line unless the points are changed
from their last operated position. On stations where point zones are track circuited flank
protection is achieved by providing track circuits in such a way that the part of the track
circuit falling within the fouling mark, if occupied shall not permit taking Òff’ the
signal for adjoining line fouling the line on which train is already standing. See `Flank
Protection’, Chapter-II, figures 7.3.10 (B-I) & 7.3.10 (B-II).
ii)
Side Collision on straight route: Side collision in station section on straight route shall
be under similar circumstances as in case of side collision in Block Section and shall be
discussed in ensuing paragraphs.
6.2
6.2.1
i)
Collision in the Block section:
Head on or head to tail collisions:
Head on Collision: In Block section head on collision may take place on single line
section or under special circumstances when single line working has been introduced on
double line section due to any reason. In case of head on collision on single line section
a) one of the possibility is disregard of Òn’ last stop signal at one of the station thereby
two trains entering into the block section simultaneously from both ends, b) extraction
of tokens at block stations at both ends of the block section, or c) Erroneous issue of
authority to proceed the last stop signal at danger when a train is already in section,
when the Block Instrument is defective or the Block Working has been suspended for
any reason.
122
ii)
Head to tail collision: In double line section another train could enter the block section
due to a) disregard of the Òn’ last stop signal, in such as situation the collision may be
averted if both the trains maintain equal speed and the leading train does not stop in the
Block section. b) Erroneous issue of authority to proceed the last stop signal at danger
when a train is already in block section, when the Block Instrument is defective or the
Block Working has been suspended for any reason.
iii)
Investigation:
a) Seizure of record: Train movement Log register, private number books of the
Station Master and both the cabins, Relay Room key register and Loco Pilots diary
of record should be seized at both the stations in between which the collision takes
place,
b) Statements: Statements of Station Master on duty, Cabin Masters on duty of
departure end at both the stations, Loco Pilot & Assistant Loco Pilot and the Guard
of both the trains and Section controller, shall be recorded.
c) Inspection & tests: Position of levers in both cabins and position of slides in SM’s
slide frame shall be recorded. If the key of the relay room is found to be under issue
at the time of accident, the relay room shall be examined for any temporary
connections and observations shall be put on record. The position of Block
Instruments at both the stations shall be recorded. The Block instruments shall be
tested for proper working at both ends and observations shall be put on record.
d) Preparation of sketches of site: A sketch shall be prepared to show point of drop,
drag and other significant observations.
e) The data to establish time of taking Òff’ relevant signals shall be retrieved in case
data logger is provided at the station. All information thus collected shall be
analysed to establish the cause
6.2.2 In case of side collision in Block section, which may occur under similar conditions i.e.
a derailed train infringing with the adjoining line, the communication from site of accident
should be jointly tested to ensure that there was no communication failure during the period of
occurrence of side collision in the Block section, which otherwise could have been saved had
there been no communication failure. This should be put on records and signed jointly.
7.
Accidents at level crossing gates: Level crossing gates are the intersection pint of
railway and road traffic at the same level. In terms of railway Act Railway has first priority
between rail and road traffic.
Out of about 38000 level crossing gates, 21500 are unmanned on entire railways. Out of
remaining manned level crossing gates 40% are Interlocked (Indian Railway safety by Arya
Bhushan & M.M. Agarwal). Each interlocked gate is protected by Signals prewarned by a
Warner or Distant depending upon the type of signalling in the section.
Interlocked level crossing gates may fall within station section and Block section. The level
crossing gates falling with in the station section are protected by the signals of the station and
the gates falling in the Block section have independent set of Gate signals on either side of the
gate. Closing of gates and taking Òff’ of the relevant signal is done by the gate man on duty.
123
The gateman is also responsible for protection to the Rail traffic across the gate, which
eventually applies to Road traffic as well. In both the cases the Level crossing gate is connected
with the Station Master of adjoining station preferably the nearest one.
Accidents usually take place due to speeding road vehicles hitting the barriers or the leaves of
the gate and infringing with the railway track while the train is approaching the gate. This may
be inadvertent or deliberate forcing in the process of closing the gate for road traffic. The Loco
Pilot not getting enough braking distance may hit the road vehicle.
Accidents at Level crossing gates though result in more casualty but are easier to resolve.
8.
Fire in trains: Fire in trains may be the result of crying inflammables, or fire works by
passengers getting ignited by a careless smoker. Often the electric conductors wired for fan &
light getting short circuited. Whatever may be reason the fire gets wild within no time due to
heavy wind. Usually casualties are high in such cases. The communication between train crew
and the station master, or Emergency control should be immediately tested jointly for efficient
working at the time of accident.
9.
Parting of train: Train parting in itself is not as serious as after affect of the same.
After parting if the rear end cut-off part does not get braked automatically and continues to roll,
it may result in collision with its main part. As such it is necessary that the main part of the train
continues to move ahead till the rear truncated part does not come to a stop. In case both parts
collide the action shall be taken in the same manner as to be taken in case of collision.
10.
In complete arrival of the train at the station: In case a train gets parted in the Block
section and the truncated part is left out. The action shall be taken to protect the part of the train
left out in the section.
11.
Vehicles escaping from the station: If any vehicle escapes from a station, the Station
Master shall take immediate steps to warn other stations or persons concerned, as far as
practicable, to prevent an accident. [GR 6.11].
*****
124
Chapter V Self Assessment
1
2
A derailment on a point could take place due
to:
a) Sharp wheel flange
b) Improper setting of points
c) Movement of point under wheel
d) Any one of above*
Flank protection is:
a) Protection against a side collision of
trains with a train standing fouling
adjoining line*
b) Protection of a train against getting hit
from the rear end
c) Protection of a train against getting hit
head on
d) Protection of a Motor Trolley against
getting hit by a train
3
4
5
Give the correct size out of the following options
of wheel flange below which, it is not permitted
to be used on high speed train:
a) 22 mm*
b) 24 mm
b) 26 mm
d) 25 mm
Fire in train usually takes place because of the
following reason:
a) Short circuit in electric wiring of coaches
b) Carrying inflammable material by
passenger
c) Careless smoking by passengers
d) Any one of above*
Minimum permissible thickness of wheel flange
is (see SOD):
a) 16 mm*
b) 20 mm
c) 18 mm
d) 15 mm
1
2
3
Main reason of accidents on interlocked level crossing gate are breaking the gate while ruthless driving
by road vehicle driver. True*/False
In case of parting of train the Loco Pilot should immediately stop the train attached with the Loco.
True/False*
All investigations should be done jointly with the team of departments apparently involved in the
accident including Operating department & Civil Engineer department. True*/False
1
2
3
4
5
Elaborate main reasons of collision & side collision in station section.
a) Possible causes of head on collision in Block section.
b) Riding of wheel on tongue rail at points.
a) Investigation in case of accidents.
b) Tests to be conducted after accident to establish that the S&T equipment relevant to the
accident were functioning properly at the time of accident.
What is an Accident Relief Train? In what way it serves the purpose in case of accidents?
What is the 1st duly of Railway employee & what action shall be taken on having come to know about
an accident.
*****
125
CHAPTER –VI
AFFECTS OF TRACTION ON SIGNALLING SYSTEM
1
Affects of Steam and Diesel traction on signalling system: Indian Railway has been
using Engines propelled by steam for more than 50 years. Diesel engines were also pressed in
service while simultaneously phasing out steam loco motives. Both of these systems of traction
were responsible for creation of atmospheric pollution. In both of these locos the foot plate for
the Loco Pilot is not in the centre of the length of the loco. In steam loco motives the foot plate
was at the end of the main body as the front part contained furnace and the boiler with a tender
attached to it carrying coal which was the fuel to create steam. In diesel Loco similar is the
orientation. It contains longer hood which carries the diesel engine leading with a smaller hood
at the rear end of the loco to accommodate braking system equipment.
Wile steam loco hauled the train essentially with longer hood leading, the diesel locos haul the
train with shorter hood leading. However there is no constraint in diesel loco hauling the train
with longer hood leading except that visibility gets obstructed for shorter distance when the
engine hauls the train with longer hood leading.
When the loco moves with longer hood leading, the 42 feet lock bar which is mechanical track
locking arrangement, is required to be placed between starter signal and the first facing point, for
the train starting from loop line. When track locking is through track circuit, the same track
circuit also works as signal replacement track. When the loco with longer hood leading, passes
the signal the track circuit should start at such a place that the Loco Pilot does not see the signal
getting back to Òn’ because of occupation of the track circuit by the leading wheels of the loco.
This distance is about 13 metre, almost the same as the length of the lock bar. This compels the
signal to be placed 13 metre behind the beginning of the track circuit. The position nearest to
the first facing point where the track circuit shall start is the stock joint. In both the situations the
clear available berthing portion of the loop line is reduced by 13 metre on this account only. If A
fouling bar or clearance bar is provided at the entry end of the loop line another 13 metre are
reduced.
With the introduction of double ended diesel engines similar to Electric Locos, it shall be
possible to eliminate this avoidable loss of berthing space. However till long hood diesel engines
are in use the provision shall have to be kept to avoid occurrence of even one incidence of the
Loco Pilot observing signal going Òn’ before he crosses it.
2
1500 Volt DC traction: DC electric traction with 1500 Volts was introduced in 1925,
when the first section of 16 kilometres was brought into use between Bombay- VT to Kurla. It
was extended upto Pune and Igatpuri by 1930. The southern Railway Metre gauge line between
Madras Beach to Tambaram was electrified in 1931. The Bombay (now Mumbai) and Madras
(now Chennai) suburban section of 388 route kilometres was energised by 1936.
126
3000 Volt DC traction: After a lapse of 20 years, after introduction of 1500 V DC
3
traction, 3000V DC traction was introduced in 1958 in Calcutta (now Kolkata) suburban section
in Howrah – Burdwan section.
3.1
The structure to hold the overhead DC traction alignment infringe with the visibility of
the semaphore signals as such only colour light signals are required to be used in DC traction
area.
3.2
Since in the area provided with DC traction, the traction return current has to pass
through rails, a DC track circuit can not be used. In its place either of the following devices shall
be used to detect track clearance:
3.2.1
3.2.2
3.2.3
3.2.4
AC track circuits with either two position or three position relays,
Jeomont track circuit with 83 ½ pulse,
Audi frequency track circuits,
Axle Counters.
4.
25 Kilo Volt AC traction:
4.1
France having introduced 25 KV AC traction in 1951 had the enough experience in
running trains on 25 KV AC traction as such Indian railways decided to go for appointment of
French National Railway (S.N.C.F.) as consultants. First section between Raj Kharsawan &
Dongaposi was introduced with 25 KV AC traction on South Eastern Railway in August’ 1960,
thereafter 18312 route Kilometres of AC traction has been provided by the end of 2008 financial
year which works out to be 28.6 % of 63968 route kilometres on Indian Railways, so far.
4.2
Traction sub-stations: Traction sub-stations are placed by the side of the track, which
receive 132 KV three phase power supply from the grid of the respective State Electricity Board.
The transformers placed at the traction substation step down 132 Volt supply to 25 Kilo Volt
and feed to the Over Head Equipment (OHE). The other end of the transformer winding is
firmly earthed to the ground at the substation.
4.3
Single phase: Since the three phase supply received from the grid system is used as
single phase for running the trains, the other phases are used in cyclic order with adjacent
subsections to avoid unbalance. The subsections are isolated from each other by providing
neutral sections of about 41 metres, in between. The neutral section is reduced to 5 metres using
special insulators in Automatic Block sections.
4.4
i)
ii)
The OHE: The OHE is in three parts
Contact wire of 107 sq mm cross-section, is grooved Cadmium Copper conductor and is
in contact with the pantograph of the engine,
Catenary, a Cadmium Copper conductor of 65 sq mm cross-section is to hold the contact
wire straight by supporting the contact wire by droppers of 5 mm diameter spaced at
about 9 metres, to adjust the natural sag of the Contact wire. The current carrying area
of both becomes 157 sq mm permitting 600 Amperes current on single track.
127
4.5
Support: The entire system is supported by cantilever bars fixed on masts placed at an
interval of 72 metres. For BG and 63 metres on MG. The contact wire is staggered by 300mm to
have uniform wear and avoid cutting of the pantograph of the loco.
4.6
Anchor: The OHE conductors are terminated at an interval of 1.5 to 2 kilometres, the
overlap span is anchored with mast with an insulator in between, while other end is provided
with counterweights to maintain equal tension all the time compensating for the expansion and
contraction during atmospheric temperature variations. The anchoring is done to facilitate
smooth transition of the pantograph of the engine from one contact wire to another.
Signal should not be placed under the live anchored conductors without additional precautions
and as such signal implantation is required to be reoriented if it falls under the anchored wire.
4.7
4.7.1
4.7.2
4.7.3
4.7.4
Affects of 25 KV AC traction: The signalling system is affected due to:
Impaired visibility of signals obstructed by the OHE structures,
Electrical clearance of the signals with the live conductors,
Traction rail return current, and
Electrostatic and electro magnetic induction.
4.8
Visibility & electrical clearance of the signals from live OHE: The structure to hold
the overhead AC traction alignment along with insulators, infringe with the visibility of the
semaphore signals. The visibility for Colour light signals is manageable as such only colour light
signals are required to be used in AC traction area [SEM 22.2.1] with the following precautions:
4.8.1 Under no circumstances any part of the signal or work man on the signal post shall
come within 2000 mm from a live OHE conductor [SEM 22.2.6].
4.8.2 In case it is unavoidable and any part of the signal or the person working on the signal
post has to infringe the zone within 2000 mm from the live conductor, a metallic screen shall be
provided between the signal and the OHE conductor and earthed.
4.8.3 The stop signal shall be placed ahead of neutral section at 1600 metres from the neutral
section if the gradient in the area is 1 in 300. The distance shall be increased to 2500 metres if
the gradient is more but less than 1 in 200. If PTFE type short neutral section is provided, the
distance my be reduced to 400 metres [SEM 22.2.8.3].
4.8.4 If the OHE mast is placed in front of the signal towards and approaching train, it shall
affect visibility adversely as such the distance between OHE mast and the signal shall be kept 30
metres at least. In addition it also must be ensured that no OHE mast falls within a distance of 10
metres ahead of signal looking from the direction of approaching train [SEM22.3.1] (Fig 4.8.4).
OHE MAST
30 m (min)
10 m (min)
TRAIN
Fig 4.8.4
Minimum distances between signal and the OHE masts
128
4.8.5 The height of the signal post or any part of the signal without route indicator shall not be
more than 5.2 metres from the rail level, maintaining the centre point of the red aspect of the
signal at a height of 3.65 metres. The rail level is measured from the top of the rail. [SEM
22.3.3.2].
4.8.6 The OHE masts shall be placed staggered for proper visibility of the signals to the Loco
Pilot in the manner given below. Figure 4.8.6.a, 4.8.6.b, 4.8.6.c & 4.8.6.d, show the
arrangement for colour light signal, without rote indicator for 1000 metres visibility, without
route indicator for 600 metres visibility, with route indicators without horizontal arm for 600
metres visibility and with route indicator with horizontal arm for 600 metres visibility
respectively [SEM 22.3.3 & 22.3.5]. If the signal is provided between tracks, no OHE structure
shall be provided in the track space at least for a distance of 600 metres in rear of the signal
[SEM 22.3.4.1]. The measurement is shown between track centre & the centre of signal post:
CENTER LINE OF TRACK
400
270
190
110
0
80
Fig 4.8.6. a
Placement of OHE masts out side track for Colour light signal without route indicator for
visibility of 1000 meters
240
160
115
70
0
50
Fig 4.8.6. b
Placement of OHE masts out side track for Colour light signal without route indicator for
visibility of 600 meters
129
280
215
170
130
0
70
Fig 4.8.6.c
Placement of OHE masts out side track for Colour light signal with route indicator without
horizontal arm for visibility of 600 meters
310
250
215
170
125
0
60
Fig 4.8.6. d
Placement of OHE masts out side track for Colour light signal with route indicator with
horizontal arm for visibility of 600 meters
4.9
Traction rail return current: The system being single phase the electric motors of the
loco form circuit with phase being the contact wire through pantograph and the return current
through rail, firmly earthed at feeding post to work as neutral. Approximately 300 amperes
current flows through rails due to operation of one loco. The return current finds its path through
any contact with the earth. This was best meat with the steel trough sleepers to give access to
return current through ballast. However with the use of PRC sleepers specifically designed to
130
provide electric isolation between rails to enable provision of track circuit, the leakage path to
earth also gets obstructed and the return current has to travel through rails only to be earthed at
feeder point where the rails are firmly earthed. This leads to:
4.9.1 Use of DC track circuits, to avoid interference with Alternating return current:
Only one rail has to be used with the DC track circuits while other rail is used to give path to the
return current. For this, accordingly, negative polarity rail of the DC track circuit is shared with
the traction current return rail. The polarity of the DC track circuit is required to be staggered to
avoid unwanted energisation of the adjoining track circuit in case of damage to the rail
insulation joint as the negative rail is already common to all the track circuits. The negative rail
of DC track circuit which is traction current return rail also, is connected with the Mild Steel
(MS) flat with the adjoining traction current return rail till the last track circuit and after that
both the rails are connected together with MS flat to give continuous connectivity to the feeder
where the rail is firmly earthed. Fig 4.9.1 a
BOTH RAILS CONNECTED AT THE END OF DC TR. CCT. BY OHE BOND
+VE RAIL
- VE RAIL
+VE RAIL
- VE RAIL
OHE BONDS FOR
TRACTION RETURN
CURRENT PATH
- VE RAIL
- VE RAIL
+VE RAIL
+VE RAIL
FEEDER POINT
Fig 4.9.1. a
Arrangement showing sharing of one rail of DC track circuits with traction return current rail
There always is possibility of traction return current passing through track relay through the
wheel of the loco in contact with positive rail to find a path through traction rail return, which
may result in picking up or burning of the track relay. For the protection of track circuit
equipment a choke of 120 ohms impedance and 3 ohms resistance is provided in the circuit. Fig
4.9.1.b.
- V E R A IL
+ V E R A IL
+ V E R A IL
F E E D E R P O IN T
- V E R A IL
R ELAY
CHOKE
V A R IA B L E
R E S IS T A N C E
+
-
CHARGER
Fig 4.9.1. b
Arrangement showing basic circuit diagram of DC track circuit with protective choke
131
4.9.2 Maximum permissible length of DC track circuit on wooden sleepers is 450 meters
and on Pre-stressed Reinforced Concrete Sleepers (PRC) sleepers it is 350 metres.
4.9.3 Measurement of stray current and stray voltage: Un-foreseen stray current flow is
observed in certain area due to industries in vicinity or other flow of currents through earth
which in-turn result in track not getting shunted to drop the track relay. It is therefore important
that stray current is measured before commissioning of new track circuits. Both rails of the track
circuit are insulated on either end and connected together. Two earths are provided at either end
of the track circuited part and a milliamp meter is provided to measure flow of current between
both rails electrically joined together and the earth to measure stray current Fig 4.9.3.a.
Similarly to measure stray voltage a resistance equal to the resistance of the track relay is
inserted between both rails electrically joined together and the earth and voltage is measured
across the resistance Fig 4.9.3.b.
The length of the track circuit shall be suitably reduced to bring the i) rail to earth voltage
measured across resistance to be not more than 100 mili volts, ii) the stray current to be not more
than 10 mili amps for the length of the track circuit of less than 100 metres and, iii) 100 mili
amps for the length of the track circuit to be more than 100 metres. It is more appropriate to
provided electronic or AFTC in such areas where stray voltage or stray current is detected.
milliamp meter
volt meter
Fig 4.9.3.b
Measurement of stray voltage
Fig 4.9.3.a
Measurement of stray current
4.9.4 Other track circuits such as Audio Frequency Track Circuits (AFTC) or Jeomont track
circuits with impedance bonds to keep the traction current balanced in both the rails thereby
keeping the potential difference between the two rails nil or bare minimum not enough to disturb
the track circuit system.
4.9.5 Axle counters are also used as alternative to track circuits which are not affected by the
traction return current as these do not form any part of the rail structure.
4.9.6 Track in the area of 25 KV AC traction is likely to be on higher potential as compared to
earth. The rod run connected to operate points at one end and to the lever frame at the other end
is therefore isolated electrically from the track by providing rod insulators between the
adjustable crank and the point connecting lug at point end and between the vertical crank and the
accommodating crank at the lead out. Similarly rod connection between point and detector,
electric point machine and trap or point indicator is also provided with rod insulators to
safeguard the maintenance staff against the electric shock. Some more precautions to be taken
are:
132
i)
ii)
iii)
iv)
v)
vi)
In case the length of rod run is more than 300 metres, additional rod insulators shall be
provided to restrict the length between two insulators, within 300 metres.
While providing insulators it shall be ensured that insulated part of rod does not come in
contact with the un-insulated rod, wire or OHE mast.
Distance between insulator and the nearest standard roller guide shall be more than 300
mm to permit maximum stroke on the tail piece.
In case of large numbers of the rodding in the same alignment, the insulators shall be
provided on each rod in the same span of standard roller guides to prevent flow of
current through standard roller guides if joints are placed in another span.
The distance between any OHE mast and that of rod run shall not be less than be 40
mm.
Wherever the rod passes under the track, the minimum clearance of 25 mm shall be kept
between bottom of the rail and top of the rod.
4.9.7 The wire operated signals are also provided with wire insulators which shall be as close
to cabin as possible as well as near signal. Some more precautions to be taken:
i)
ii)
iii)
iv)
v)
vi)
Insulator shall also be provided on detector wire in the same manner.
Distance between insulator and the nearest pulley stake shall be more than the stroke at
the lever tail.
The distance between two wire insulators shall not be more than 300 metres. In case it is
so, additional wire insulator shall be provided to keep the length between two within
300 metres.
In case of large numbers of the wires in the same alignment, the insulators shall be
provided on each wire in the same span of pulley stakes staggered in such a manner that
insulators do not entangle with each other.
Horizontal distance between two wires shall be not less than 50 mm while vertical
distance between two wires shall be not less than 200 mm.
A minimum distance of 40 mm shall be kept between wire and the nearest edge of rail
or the mast.
4.9.8 The wire run operating Lifting barriers is provided with wire insulators at winch end as
well at lifting barrier end. The boom lock arrangement shall be insulated at both, lever end as
well as boom lock end, in either case of wire operation or rod operation.
4.9.9
Installations to be earthed: Equipment to be earthed separately [SEM 22.14.2]:
i)
ii)
Lever frames and other metallic frames,
Protection screen provided on signals falling within the range of two meters of live
conductor.
All relay-racks inside relay room
Apparatus cases where the cables terminate.
Block instrument circuit working on earth return, through filter unit.
The surge arrester provided in block filter unit.
Armouring of the tail cables when the length increases beyond the prescribed limit.
iii)
iv)
v)
vi)
vii)
133
4.10
Electrostatic and electro magnetic induction:
4.10.1 Electrostatic induction-Over head alignment to be converted to underground
cable: Any conductor when charged with a potential with reference to earth, creates an opposite
charge on another conductor in its vicinity. The induced potential is directly proportional to the
potential on the main conductor and inversely proportional to the distance between the two. This
induction of charge is called static induction’. The conductor carrying 25 KV AC accordingly
creates static induction on all conductors in its vicinity i.e. track, rod run, wire run cables etc.
this induction is substantial when the conductors are running parallel to the OHE. Results of
measurements done in Sealdah Division of Eastern Railway is reproduced below:
SN Separation between OHE wire and the
Length of parallelism
Electrostatic
alignment from the centre of track
of overhead alignment
voltage measured
1
9 metres
1KM
950 V
2
109 metres
1KM
3.25 V
3
209 metres
1KM
0.9 V
This suggests that all the circuits on overhead alignment running parallel to the track shall have
to be put underground in the form of cables.
4.10.2 Electromagnetic induction – Screening of the cables: Any conductor in which current
flows, magnetic lines of forces are created around it. These magnetic lines when very due to
change in potential in the conductor and cut another conductor, an induced potential is
developed in the conductor cut by the magnetic lines. The potential so generated is called
Electromagnetic induction.
Since in case of current through OHE conductor is AC, all the conductors including rails get
influenced by these magnetic lines of forces and an induced potential is generated there. The
magnitude of this induced potential is proportional to the current, rate of change of potential in
the main conductor, distance of separation and conductivity of surrounding medium etc.
When all of the OHE current passes through track, the induced voltage in the cable running
parallel to the track shall be almost nil as induced potential getting due to OHE and rail shall
neutralise each other. However there are two situations one where the return current passes
through rail as well as through ballast and earth where sleepers other than PRC are provided. In
second case where PRC sleepers, which are designed and provided with additional insulators for
bearing track circuits, the entire traction return current has no path other than rail.
It was decided to provide the cable with lead or aluminium sheath and the sheath to be earthed.
The voltage induced in sheath caused flow of current, the sheath being earthed. This resulted in
neutralising & as such reduction of induced voltage in cable, & provided screening effect.
4.10.3 Maximum voltage induced on cable: The entire network of flow of current through
contact wire, railway track, earth and other metallic conductors in the vicinity, conductivity of
earth, cumulatively result in generation of potential 95 Volts per kilometre on unscreened
armoured signalling cable used in double line section taking return current as 600 amperes,
where 35 is the voltage induced on screened cable per 1 kilometre. The induced voltage on a
single line section on unscreened cable is 116 Volts per Km taking return current as 300
134
amperes. [SEM 22.6.2.1]. This has far reaching affect on the entire signalling system in 25 KV
AC traction area.
4.10.4 Reduction factor: Rail reduction factor of 0.4 on double line and .56 on single line
section, along with other factors taken into consideration results in development of induced
voltage of 35 Volts per Kilometre on screened signalling cable. The sheath of the cable was
required to be earthed at each termination and the screening effect was depended of the
effectiveness of the earth. Over the period it was observed that maintenance of earth was far
from satisfactory. A 300 volt signalling system was designed using un-screamed cable. It was
difficult to handle as too many precautionary measures were required to be taken and the system
was changed soon to use 110 V AC supply using unscreened cable with provision of cutting in
relays at shorter intervals, which is in vogue today.
4.10.5 Maximum length of parallelism: Two factors are there to decide maximum length of
parallelism. i) Human safety and ii) system safety.
240 METRES (MAX)
>
HR
NX110
110:12
2.3 V
)
21 V
>
BX110
HR
SIG. LAMP
)
ii)
Human safety: Upto 120Volts can be handled by human being safely. As such
maximum length for unscreened cable has been permitted to be 1.2 kilometres.
System safety: The unsolicited induced voltage if not taken care can result in unsafe
conditions:
a) Limit for direct feeding of signal lamps: In case of incandescent Signal lamps
which work on 12 Volts AC, the glow of the lamp is proportional to the voltage
applied. These lamps glow at 2.3 volts. In case of a typical double earth fault in the
cable, where the power to the lamp is extended by HR placed in the cabin if 21 volt
is induced in the cable on the primary sided 2.3 volt shell appear on secondary side
under transformation ratio of 110:12. This restricts distance for direct feeding of
signal lamp as (21/95) x1000=240 metres. This distance, with screened cable is
(21/35) x1000= 600 metres. Fig 4.10.6
)
i)
)
Fig 4.10.6
Maximum permissible distance for direct feeding of signal lamp to protect against
glowing of lamp in two earth faults case
Accordingly the maximum permitted length for direct feed of signal prescribed as per
SEM 22.7.3 is tabulated below:
Type of cable
110 Volt feed system
300 volt feed system
Single track
Double track Single track
Double track
Screened
600 m
600 m
--Un- screened 180 m
220 m
500 m
500 m
135
b) Use of AC Immunised relays in outdoor circuits: Indoor circuits are designed
with single wire using no-AC immunised relays, while outdoor circuits are designed
with double wire using relays which are immunised to 400V AC [SEM 22.6.2.2] to
avoid picking up of relays due to induced voltage in the cable.
c) Cutting – in- relays: In view that a potential of 120 Volts is induced through a
length of 1.2 metres of unscreened cable, a relay shall be inserted at this distance to
cut-in the length to keep 120 Volts limit. The next relay shall be picked up through
pickup contact of this cutting in relay with a different source of power supply. All
relays used in out side circuits shall be immunised to 120v x 2.5 = 300 Volts AC
keeping a factor of safety of 2.5 times of 120 V.
d) Separate power supply source for indoor & outdoor circuits: Since the indoor
circuits are designed on single conductor using non-AC immunised relays the power
supply source for indoor circuits shall be separate to the power supply source for
outdoor circuits [SEM 22.5.5].
e) Power supply source for outdoor circuits: shall be so grouped that at any source
the total length of circuit never increases beyond 1.2 kilometres when unscreened
cable is used on double line (95v x 1.2m =114m i.e.< 120m) this length may be
increased to 3.5 kilometres if screened cable is used (35 x 3.5 = 122.5).
In case signals are placed at a distance beyond 1.2 kilometres when unscreened
cable is used and by 3.5 kilometres when screened cable are used, the signals are to
be feed from different source of power supply, such as in case of distant signals, a
separate source of power than the main outdoor source of power supply shall be
used for the same.
f) Equipment not immunised to AC: Some equipment are not immunised to AC. To
take care of this, command for operation of such equipment can not be given
directly. One relay which is AC immunised is picked up at the site of such
equipment to communicate command and the equipment is operated through local
circuit in a manner similar to other indoor circuits. These equipment are listed below
[SEM 22.5.3]:
i)
Luminous indicators,
ii)
Telephone type relays,
iii) Electric Lever Locks,
iv) Door coil of IRS Block Instrument,
v)
250 Ohms DC neutral line relays,
vi) Rotary key transmitters,
vii) Arm & Light repeaters,
viii) DC neutral polar relays.
g) Relays which release interlocking shall be slow to act with time delay, ranging
between 0.6 to 0.8 seconds so that interlocking is not released due to inadvertent
voltage fluctuations. [SEM 22.5.8].
h) Length of DC track circuits terminated on Line relays with unscreened cable shall
be restricted to [SEM 22.6.2.5]:
136
Type of relay
AC immunity level Maximum permissible length on*
in volts
Single line
Double line
AC immunised shelf type 750
2.1 Km
2.8 Km
QNA 1
1000
2.1 Km
2.8 Km
K50B 1
170
1.0 Km
1.2 Km
K50
130
750 meters
900 meters
* Maximum permissible induced voltage is restricted to 400V for human safety &
factor of safety 1.5 has been considered.
j)
Electric operation of points: The maximum permissible length for various type of
commonly used point machines is as under [SEM 22.8.2.2]. This is keeping factor
of safety as 1.5:
Type of
Machine
AC immunity
level in volts
IRS-24
SGE 110V
GRS 5E
Style 63
M3
M5
Siemens IA
Siemens IB
Siemens IC
LM-55
160
250
90
130
200
70
160
300
400
160
Maximum permissible parallelism in meters between
point contactor & point motor
Single line
Double line
910
1100
1435
1750
515
630
745
910
1150
1400
400
490
910
1100
1650
2100
2200
2800
910
1100
4.10.6 Block working: In 25 KV electrified area only following type of block instruments can
be used: [SEM 22.9.1]
i)
On single line section:
a) Neal’s token instrument;
b) Daido’s Token-less instrument;
c) Block working with Axle Counter;
ii)
On double line section:
a) SGE Block instrument;
b) Block working with Axle counter.
c) Push button type block instrument may be used on non electrified section taking off
from electrified section if the length of parallelism does not exceed 1.5 Km.
4.10.7 Additional precautions to be taken for Block working:
i)
Poly Ethylene Tetrachloride (PET) insulated Quad cable shall be used to connect two
block instruments of which one quad shall be used for block instrument and half quad
shall be kept as spare. The block instrument shall be connected through a filter unit to
protect the system from high induced voltage.
137
Both the half quads of one quad shall be terminated on transformers of ratio with its
primary side to match the characteristic impedance of the cable and secondary side to
match the characteristic impedance of the equipment i.e. one for Block bell & other for
Block telephone see fig. 4.10.7.
The block instrument shall work on earth return phantom circuit.
The telephone attached with the block instrument shall be used on one half quad through
the transformer with induction coil.
The block bell shall work through an independent Block Bell Equipment to be
connected through the transformer connected on the other half quad of the cable.
The filter unit consists of two chokes S1 of 50 Ohms resistance & 40000 Ohms
impedance and other S 2 of 40 Ohms resistance & 20000 Ohms impedance. Two
capacitors C1 each of 10 mfd and two lightening dischargers LD, connected to common
earth. The arrangement is shown in figure 4.10.8.
Ripple free power supply for the line circuit shall be used. For this either primary cells,
DC-DC converters of IPS or Battery Charger with dual battery bank shall be used as the
three position magnetic polarised relay is not immune to AC.
ii)
iii)
iv)
v)
vi)
vii)
CABLE TERMINATION BOX
PET CABLE
T1
T2
BELL
TELEPHONE
BLOCK FILTER
S1
S2
BL. INST.
LINE 2
C1
LD W
EARTH
W
LD
C1
S1
LINE 1
S2
Fig. 4.10.7
Arrangement of connection between cable termination box and block filter
viii)
Another battery set shall be used for working block bell equipment. This may also be
clubbed to signalling internal battery set.
4.10.8 Laying of the cables: Cable laying shall be done based on following principles:
i)
The cable running parallel to the track shall be buried at a depth of 0.8 metres from the
ground level and while crossing under the track shall be 1 metre below the bottom of the
rail. In case of rocky soil the depth may be reduced to 0.5 metres.
ii)
In case of tail cable the depth shall be not less than 0.5 metres.
iii)
The distance between OHE mast and the cable trench shall be not less than 3 metres to
maintain depth of the trench more than 0.5 metres.
138
iv)
v)
vi)
vii)
viii)
ix)
A distance of one metre shall be maintained between the cable and the OHE mast
supporting Catenary or any structure that is likely to come in contact with high tension
conductors. In this case depth of the cable shall not exceed 0.5 metres. The distance of
the cable from OHE mast may be reduced to 0.5 metres by passing the cable through
RCC pipes near the OHE mast
In vicinity of the traction substation or switching station such as Feeding posts,
sectioning posts and sub sectioning posts, the cable shall be laid one metre away from
any metallic body of the substation which is fixed in the ground. The distance of one
metre shall also be maintained from the substation earth.
All the traction return current flows through sub station earth as such a) the cable shall
be laid on the side of track opposite to substation or, b) on the side of substation,
through RCC pipe or enclosed brick channels, for a length of not less than 300 metres
on either side of the sub station.
The cable shall be laid at least 5 metres away from the switching station earthing which
can be reduced to one metre by passing the cable through RCC pipes near the earth.
Signalling, telecomm and power cable can be laid in the same trench observing
following requirements:
a) 100 mm distance between signalling and telecomm cable shall be maintained.
b) Signalling and power cable shall be separated by row of bricks.
c) For recognising the cables in the same trench, the telecommunication cable shall be
laid nearest to the track, signalling cable spaced by 100 mm next to
telecommunication cable away from track and power cable separated by row of
bricks outermost away from the track. If LT and HT both cables are laid in the same
trench as signalling and telecom, the HT cable shall be put outermost and LT by the
side of bricks.
d) A separation of 50 mm shall be maintained between the power cable and signalling
cable when laid in separate trenches.
Cables shall cross the track:
a) Right angle to it.
b) Shall not cross under the points and crossings.
c) Pass through RCC pipes at a depth of one meter below bottom of rails.
d) Minimum distance of 0.2 metres shall be kept between signalling and power cable.
e) When cable has to cross a metallic bridge it shall be placed inside GI pipe filled
with sealing compound suitable to withstand 6000 V AC.
*****
139
Chapter VI Self Assessment
1
2
Minimum glow voltage of a incandescent
signal lamp is:
a) 6.3 Volts
b) 4.3 Volts
c) 3.3 Volts
d) 2.3 Volts*
In case of 25 KV AC traction when
signalling, telecomm & power cables are laid
in the same trench running parallel to track,
the power cable shall be laid in the trench
placed:
a) Nearest to railway track
b) Middle of the trench
c) Farthest to railway track*
d) In between signalling & telecomm
cable
3 Maximum permissible parallelism in meters
between point contactor & point motor in case of
25 KV AC traction area, for Siemen’s-lc point
machine is:
a) 1100 mts
b) 2100 mts
c) 2800 mts*
d) 490 mts
4 With the use of unscreened signalling cable in
25 KV AC traction area the induced voltage per
Km on double line section is:
a) 75 V
b) 95 V*
c) 99 V
d) 100 V
1
2
3
4
5
The Block instruments are the only equipment in 25 KV AC traction area operated on single
conductor circuit through earth return. True*/False
Only single rail DC track circuit may be used in case of 25 KV AC traction area. True*/False
Relay which release interlocking shall not be slow to release. True/False*
In 25 KV AC traction area block bell shall work on alternating current, through a Block bell
equipment. True*/False
The three position relay used in series with line circuit due to which ripple Block instrument power
supply can only be permitted on line. True*/False
1
2
3
4
5
6
List out equipment which are not immunised to AC for use in 25V AC traction area.
Discuss salient features of power supply arrangement for signalling system in 25 KV AC traction area.
Draw schematic diagram depicting Block Instrument circuit connecting to quad cable through
transformers.
a) Affect of 1500 & 3000 V DC traction of signalling system.
b) Affect of 25 KV AC traction of signalling system.
a) Types of track circuits which can be used in 25 KV AC traction area.
b) Compare utility of the track circuits used in 25 KV AC traction area.
Detail precautions to be taken while using SGE type double line Block instrument, in 25 KV AC
traction area.
*****
140
Bibliography
1.
2.
3.
4.
5.
6.
Indian Government Railways General Rules 2007;
Compendium on Instructions on matters pertaining to condonation of
infringements to schedule of dimensions, CRS & Railway Opening of Public
Carriage of Passenger Rules issued by CORE;
Signal Engineering Manual Part-I, 1988 & part – II 2001;
Objective Railway Engineering by M.M. Agarwal;
Notes on signalling in 25 KV Electrified sections by IRSTE, Secunderabad;
Indian Railway Safety by Arya Bhushan & M.M. Agarwal.
*****
141
INDEX
A Marker
26
Absolute Block system
59
AC traction 25 Kilo Volt
127
Accepting Authority (Tenders)
84
Accident Relief Train (ART)
117
Accidents at level crossing gates
123
Addition of new item of work
86
Additional fixed signals in Automatic
64
Block territory on single line
Additional precautions for block
137
working
Advanced Starter signal
34
Affects of 25 KV AC traction
128
Affects of Steam and Diesel engines on
126
signalling system
Application for sanction
88
Appointment of Arbitrator
87
Approach Locking
37
Approved special instructions
7
Arbitration
86
Aspects of the signal
29
Authority to enter the section
71
Automatic Block signal
28
Automatic block system
63
Award of Contract
81
Axle counters
46
Back locking
39
Back Locking by Electrical Means
39
Back locking Mechanically
39
Block hut
9
Block Instruments
113
Block overlap
45
Block Section
15
Block Stations
8
Block Working
45,137
Briefing note
82
Cabin and Lever Frame
110
Calling-on signal
24
Capital expenditure
75
Capital fund (Cap)
75
Capital fund (CF)
76
Capital source of fund and expenditure
75
Catch siding and Slip siding
46
Catechism for signalling and
105
Interlocking installation
Categories of train accidents
116
Caution Indicator
Check and Indication Locking
Class ‘A’ Stations
Class ‘B’ Stations
Class ‘C’ Stations
Classification based on TVUs
Classification of fixed signal based on
usage
Classification of fixed signals based on
structural design
Classification of signals based on
placement
Classification of Stations
Classification of stations based on
operational requirements
Classification of stations based on
Standard of Interlocking
Clearance bar
Co-acting signal
Collision in station section
Collision in the Block section
Collisions
Colour light signalling system
Commissioning of the work
Conditions for granting Line Clear at a
class `B’ station on single line
class `C’ station
Conditions for granting Line clear at a
class ‘A’ station
class ‘B’ station on double line
Conditions for taking ‘Off’ Manual stop
signals in automatic Block territory
Construction Organisation
Contractor not applying for DOC
Correspondence between operating and
operated units
Cost of work
Cutting in Relay
DC traction 1500 Volt
DC traction 3000 Volt
Dead Approach Locking
Declaring the station Non-Interlocked
Delayed tenders
Departure signals
142
94
40
8
8
8
47
22
17
31
8
8
9
42
27
121
122
121
23
92
60
61
60
60
65
74
86
36
77
136
126
127
38
93
81
34
Depreciation Reserve fund (DRF)
Derailment on straight route
Derailments
Development fund (DF)
Devices to monitor status of the yard
Different causes of accidents
Direct reception of a train
Distant sig. in Modified, two aspect
semaphore signalling territory
Distant signal in Multiple Aspect
Colour Light signalling territory
Distant signal in Semaphore Multiple
Aspect Upper Quadrant
Distant signal in Upper Quadrant
Dock signal
Electric Operation of Points
Electrical Block Instruments of Token
or Token-less type
Electrical Communication Instruments
Electrical Signalling equipment
Electromagnetic induction – Screening
of the cables
Electrostatic induction
Enquiry into cause of accident
Equipment not immunised to AC
Essentials of Automatic Block System
on double line
Essentials of Automatic Block System
on single line
Essentials of interlocking
Essentials of the Following Train Sys.
Essentials of the One Train Only
System
Essentials of the Pilot Guard System
Essentials of the Train Staff and Ticket
System
Evolution of Indian Railways
Evolution of Railway Signalling system
Execution and commissioning of the
work
Execution of work on a running line
Execution of works
Finances for construction organisation
Fire in trains
Fixed Signal
Fixing of Caution, Speed and
Termination Indicator Boards
Flank Protection
76
120
118
76
42
116
60
32
Following Train System
66
Fouling bar
42
G Marker
25
Gate signal
25
Generally used terms
7
Goods signal
27
Grant of extension for completion of
85
work
Head-on or head to tail collisions
121,122
Holding bar
39
Home signal, Routing Home signal &
33
Route indicator
Human safety
135
In complete arrival of the train at the
124
station
Indication conveyed by the Aspect of
30
the signal.
Infringement of maximum and
100
minimum dimensions
Inspection at points
107
Inspection at the Signals
105
Inspection by CRS
98
Inspection of the cabin
108
Inspection on the track
108
Installations to be earthed
133
Interlocking
101
Interlocking in the station section
35
Interlocking of ‘B’ class level crossing
48
gates
Interlocking of ‘C’ class level crossing
49
gates
Interlocking of ‘Special’ & ‘A’ class
48
level crossing gates
Interlocking of level crossing gates
48
Intermediate block post
9
Intimation of accident
116
Inviting tenders
79
Isolation
44
Isolation at stations
102
Isolation where to be provided
44
Items not covered in SOR
79
Joint Safety Certificate
92
Junction of tracks
102
Last Accepted Rates (LAR)
81
Late tenders
81
Laying of the cables
138
Level crossing Gates
43,47
32
32
32
27
137
46
46
111
134
134
118
136
63
64
35
66
71
67
68
1
4
95
87
76
74
124
17
94
42
143
Level crossing gates falling in
49
Automatic Block signalling
Lever Lock
43
Limit for direct feeding of signal lamp
135
Limited Tenders
85
Lock bar
39,55
Locking of last trailing point by the Last
41
Stop Signal
Maximum length of parallelism
135
Maximum permissible length of DC
132
Track Circuit
Maximum voltage induced on cable
134
Means of Isolation
45
Measurement of stray current
132
Mechanical Semaphore Signal
17
Minimum equipment of fixed signals in
64
Automatic Block territory on single line
Modified lower quadrant signalling
19
Monitoring clearance of the track
42
Monitoring devices
41
Multiple aspect colour light signalling
20
Multiple aspect Upper quadrant
19
Signalling
Non-Block Stations or Class ‘D’
9
Stations
Notification to Railway officials before
87
opening works
Obstruction on a block station on
61
double Line section
Obstruction on single line in block
62
section
One Train Only System
70
Opening of minor works
99
Opening of new Railway
99
Opening of tenders
80
Outer signal
32
Overlap
45
Parting of train
124
Passing a Gate stop signal at Òn’ in
66
Automatic signalling territory
Passing an Automatic Block signal at
63
‘On’on double line section
Passing Automatic Signal at ‘On’ on
65
single line section
Pilot Guard System
67
Points (Inspection of)
109,101,111
‘Position’, ‘Aspect’ and ‘Indication’
29
signals
Post accident action
117
Post Contractual matters
85
Power operated points and signals
109
Powers of CRS to open minor works
100
Preparation for Commissioning
90
Preparation for opening of new railways
96
Protection of train on Pilot Guard sys.
68
Railway Signalling System.
7
Rate analysis for preparation of signal
78
foundation
Reception signals
32
Reduction factor
135
Repeater signal
26
Request for change in rates or tender
86
condition from contractor
Revenue expenditure
75
Revenue receipts
75
Risk & cost contract
83
Route holding
37
Rules for Opening of a railway
95
Running Line
7
Running train
7
Safety Certificate
90
Safety Certificate for S&T works for
92
introducing Electrification
Schedule of Dimensions (SOD)
49
Schedule of Rates SOR
79
Sectional route release
41
Semaphore signalling system
23
Shunt signal
23
Shunting
7
Side collision in station section
122
Siding and trap points
102
Sidings
46
Signal overlap
45
Signals (Inspection of)
109,101,111
Signals at class ‘D’ station
28
Special Instructions
7
Special Limited Tenders
85
Speed Indicator
94
Standards of Interlocking
9
Starter signal
34
Station
7
Station Limits
13
Station Section
14
Station Section and Block Section
14
Stop Signal
22
144
Switching over of new signalling
system replacing the existing
System safety
Systems of working the trains
Temporary opening of railways
Tender Committee
Tender documents
Tenders
Termination Indicator
Test to be made in the lever cabin or at
the Lever frame
Track circuits
Track Locking
Traction rail return current
Train Staff & Ticket System
Train staff Tickets, how kept
Trap siding
95
Two aspect colour light Warner Signals
32
Two aspect lower quadrant signalling
17
Two Packet System (of tendering)
84
Use of AC Immunised relays
136
Use of DC track circuits
131
Use of One Train Only System
70
Variation in the items of schedule
85
Various methods of Isolation
103
Vehicles escaping from the station
124
Visibility & electrical clearance of the
128
signals from live OHE
Visibility of signals
21
Warner/Distant signal
22,32
Warning Board
22
Works requiring notice to and sanction
88
of the Commissioner of railway Safety
135
59
99
82
80
77
94
109
46
40
130
68
69
46
*****
145

Indian Railway signaling

Transcription

Similar documents

Historic Builders SECOND HALF

Agreement Signed for the Construction of Mieso-Dire Dawa

kindergarten 2013 - Railway Town Public School

Fertagus Concession Contract

Government of Montenegro Ministry of Transport

July 92 - Electric Railway Historical Association of Southern California

Arctic ra

From Beijing to Lhasa

Bluebell Railway Press Release

- Ffestiniog Railway