Modeling Santa Fe Trestles

Modeling Santa Fe Trestles
And Other Six-Legged Trestles
Mike Barrett
Black Bear Construction Co., Inc.
Copyright 2008, Black Bear Construction Co., Inc.
All Rights Reserved.
▪Prototype Photos
Agenda
▸ AT&SF
▸ Union (Southern?) Pacific
▸ Western Pacific
▪Prototype Documentation
▸ Santa Fe
▸ Pennsy
▸ Chicago & Northwestern
▪Modeling a Round-Legged Prototype
▪Modeling a Square-Legged Prototype
Santa Fe trestle
between Lubbock
and Amarillo, TX.
Notice the
common Santa Fe
design element:
the longitudinal
braces that attach
to the horizontal
braces on the
bents.
Longitudinal
braces are present
on almost all
AT & SF trestles.
Santa Fe trestle between Rosenburg and Sealy,
Texas. Most of the Santa Fe trestles I have seen in
Texas are ballasted deck instead of open deck.
Notice the 6” x 9” x 1/2” angle plates
that join the longitudinal brace to the
horizontal brace.
Teco
Single
Curved
Grid
Teco
Single
Curved
Grid
anchors the brace to the
legs.
Santa Fe trestles south of
Post, Texas
736.7
Notice the missing longitudinal
braces.
Bridge 741.7
Another Santa Fe trestle that
does not have horizontal braces.
Bridge 741.7
Notice the shims
under the outside
floor beams.
Bridge 734.0
Notice the square timbers,
longitudinal beams, and
concrete footings.
Notice how the timber decking extends
over the abutment timbers.
Bridge
Bridge
736.9
736.9
This prototype is the basis for the diorama
that will be built later.
Notice the frame bents in the middle and
the pile bents on the ends.
Pile bent
Frame bent
Bridge 747.1
A double-track trestle at a siding
Suburban Ft. Worth, TX, trestle
with both frame and pile bents
Notice the open deck.
Square legs and round legs
Between Sealy and Brenham, Texas.
Diagonal bracing was not
common on AT&SF trestles.
Western Pacific
Altamont Pass, CA
Many timber trestles are being
replaced by concrete and steel
– and culverts.
Downtown Austin, TX
A frame
A frame bent with
round legs
UP/SP(?) trestle being replaced.
Smithville, Texas
Santa Fe, south of
Post, TX
More replacement work
We'll model this trestle
Ballasted deck
Pile
bents
Frame
bents
Reference Documentation
There are about 30 pages of trestle documentation.
1/4" x 1" Stringer Assembly
or fabricate with 4, 1/4" x 1/4"
Angle Brace
1/16" x 1/16" Styrene
7-34 " x 10" (2X)
6" x 12" (2X)
25
32 "
1/16" x 3/16" Filler
1/16" x 1/8" Sidewall
1/8" x 3/8" Decking
7-34 " x 14"(12X)
9' Long ties
5
x 5- 8 " x 6" shim spaced on 5.5' intervals
Set of 3 centered between each pair of bents
9- 34" x 10" (6X)
1/32" x 1/16" x 1/8" Block
1/32" x 1/8" x 9/16" Shim
29- 34 "
1/8" x 1/8" x 2.21" Top Cap
2" x 6" x 14" Block
4" x 14" x 3'-10" Shim
1/32" x 3/32" x 1.93"
12" x 12" x 16' TOP CAP
GL-5066 Nut-Bolt-Washer
(NBW)
3" x 10" x 14'
THE MODEL
1:1 for HO scale
AT&SF BALLASTED DECK
TRESTLE BENT
Supplemental
Drawing
May 26, 2008
THE PROTOTYPE
Santa Fe Bracing Details
18' [2.48"]
2'-9.2" [0.38"]
11' [1.52"]
Standard on all bents
7'-2.8" [1.00"]
16' [2.21"]
13'-2.8" [1.82"]
10' [1.38"]
18' [2.48"]
16' [2.21"]
12' [1.65"]
11' [1.52"]
14' [1.93"]
Standard when rail height is over 10'
16'-8.8" [2.31"]
Standard when rail height is over 16'
19'-6.0" [2.69"]
AT&SF had specific standards for the bracing on their trestle bents.
Notice that there are two ways to measure the height of the bent:
a) Height of the bottom of the rail above the ground.
b) Height of the top of the top cap above the ground.
14' [1.93"]
22' [3.03"]
22'-2.8" [3.06"]
25' [3.45"]
35' [4.83"]
32'-2.8" [4.44"]
37'-2.8" [5.13"]
40' [5.52"]
18' [2.48"]
Standard when rail
height is over 19.5'
Standard when rail height is over 25'
2' [0.28"]
22' [3.03"]
Standard when rail height is over 35'
5" x 8" Guide timbers
(1/16" x 3/32")
8" x 10" x 9' Long Ties
10" x 18" Typical for 13' to 14' spans
Spaced 2" apart
Note 3
(3/32" x 3/16")
NOTE:
3 PCS, 10" X 16" FOR 10' TO 12' SPANS;
3 PCS, 10" X 20" FOR 14' TO 15' SPANS
3" x 10" (1/32" x 3/32")
TYPICAL
6" x 10"
(1/16" x 3/32")
12 x 12 (1/8" x 1/8")
FRAME TRESTLE BENT
BASED ON PENNSYLVANIA RAILROAD PROTOTYPE DRAWINGS
1:1 in HO Scale
Pennsylvania Railroad Details
June 17, 2008
Chicago &
Northwestern
prototype drawing.
Here is the plywood layout
where the trestle will go.
OK, it's really just a diorama, but you get the idea. I advocate getting the
trains running first and worry about the bridges and scenery later.
Otherwise, there are too many reasons to never get started. So here we
are happily operating our trains.
Use the Trestle Buddy to
determine the length of the
trestle and where the
abutments will go.
Sketch in the location of the ravine.
The Trestle Buddy holds the bents
in place and keeps them vertical.
Screws attach the joints to
sectional or flexible track.
How the Trestle Buddy
goes together.
Slots allow the
joints to adjust.
Screws hold
them in place.
Lugs locate the
bents.
Notice how the blocks and lower plywood
bridge the gap where the ravine will be.
This holds everything together after we
cut out the sub-roadbed.
Continue to operate while the
scenery is being built.
Scenery is almost complete.
The day has arrived when the trestle
will be installed. Cut out the track and
sub-roadbed.
(Continue to Part 2.)