Timber trestles on the C&TT Railroad
The truss rods (above) on the Cimarron Canyon trestle are smaller in diameter in the center and become larger on the ends. This is much like the prototype. The overhead view of the trestle (left) shows how the track is offset on the truss bridge deck as it crosses the ravine. The width of the deck was designed to take the 30″ radius curve into account.
er. I’m writing about these trestles once again, along with several others that have been constructed more recently. I should say here that all of the tres- tles include either a single or double set of guard rails. Since I still have one engine and a few HOn3 cars left over from my earlier modeling days,
I
spiked the guard rails in place using an HOn3 track gauge. To see the HOn3 engine run, I temporarily connect one of the guard rails and its respective stock rail with a short piece of wire. At the present time there are eight timber trestles and two steel plate girder bridges on the layout. Six of the timber trestles are supporting curved trackage, which means that special width considerations had to be taken into account in their design.
Cimarron Canyon trestle
One of the first scenes one sees when entering my train room is the combina- tion deck truss and trestle spanning the gorge at Cimarron Canyon (See the lead photo on page 73.) The tres- tle’s track is actually part of a large re- verse loop on my Silver King Branch. It’s 40 scale feet above the C&TT main- line and on a 30″ radius curve, and the trestle and bridge spans a 180-foot deep chasm. The truss portion is 80 feet in length and 18 feet wide. Heavy timber abutments anchor
the ends
with two timber bents on the left and three on the right to support the truss. Rather than using three 8″× 24″ scale timbers, I cut the stringers to be 24″ square, then scored them with a knife blade to make them appear as though
they are made up from three pieces of timber. The bridge and trestle ties are 9″×12″×10′-0″ long, and the three fire barrel platforms are made from five ties 16 feet in length. The handlaid track was initially in- stalled across the site of the future canyon on ⁵/₈″-thick industrial particle board (IPB) sub-roadbed. I made par- tial cuts through the IPB and support- ed it with risers that eventually would become supports for the end abut- ments when the trestle and bridge units were completed.
I made a paper template of the actual
track radius by laying a large strip of in- dex card stock atop of the curved track at the trestle’s location and rubbed along the rail heads with my fingers to create an impression of the rails. On lat-
The abutment (above left) for the Cimarron Canyon trestle is out- fitted with an alignment key. This is a notch that allows the entire trestle to be removed and reset while scenery work is in
74
progress. A close up view of the trestle (above right) reveals the homemade epoxy nut-bolt-washer castings as well as the three sets of timbers that make up each side of the truss span.
SEPTEMBER 2013
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