Timber trestles on the C&TT Railroad
The Ponderosa Jct. trestle (above) is supported by carved rock abutments on each end. The truss portion has straight track and is in the easement section of a 30″ radius curve. The ends of the
Two large stringers with their ac- companying trestle-length ties were fashioned to sit on these abutments. However, unlike the other trestles on the layout, this one was designed with the rails remaining in place while the deck was slid in place below them. All I had to do before re-installing the fascia was to mark and make the cuts to see the new gully. Before the scenery was in place it was possible to completely remove the trestle deck, but it’s a little difficult to do it now. And, since there’s no reason to remove it now, it’s not a big deal.
The trestles at Tall Timbers and Ponderosa Junction There is a small curving, open deck trestle near the enginehouse at Tall Tim- bers, and it is among the first things a visitor sees when entering the room. At about 90 scale feet long, it spans a small ravine that’s close to 30 feet deep. The abutments at each end are a little differ- ent from one another. One features heavy timber cribbing that has been filed with rock, while the other is basical- ly a heavy timber retaining wall.
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diagonal timbers (right) are notched and set into their respective chords. This detail was only done on the visible side, while the di- agonal elements on the other side were butt jointed together.
There are two fire barrel bays on the
bridge, as well. The timber bents rest on simulated concrete bases that were put in place after the trestle was in- stalled on the layout. The bases were coated with a thin layer of drywall compound and smoothed out with my finger to represent poured concrete. Like the others, the trestle can be re- moved by slipping the rail joiners out of the way and lifting it upward. I de- signed keyways into the abutments, so the unit is quickly aligned when it is dropped back into place.
The last wooden bridge discussed in this article features a 73-foot long-deck bridge with a Warren truss; it supports the curving rails of the reversing track on the upper level. The reversing loop allows trains descending the four per- cent grade at Silver King to head downgrade with their engines at the front to prevent run-aways. As with the other trestles in this article, the plans were developed using Cadrail and printed out on index card stock. Strip- wood was cut and temporarily tack- glued onto the drawing during con- struction. Rather than incorporating
angled plates for the front side diago- nal braces, I notched out both the top and bottom chords to accept them in- stead. Since these junctions between the diagonals and chords wouldn’t be too visible on the other five side compo- nents, I simply cut the diagonal pieces at an angle and glued them in place on the chords.
The small brads mentioned earlier were also employed to secure the cross timbers in place. Since the track is eas- ing into a curve as it crosses the deck, additional width was allowed when de- signing the span. Chemically black- ened music wire was used to represent the truss rods, and their end details were cast from epoxy using the n.b.w. molds created for the Cimarron Canyon trestle a few years earlier. I hope that some of the things men- tioned here will lead you to scratch- build a trestle or two of some style for your railroad. There are plenty of books to use for reference, and the In- ternet makes it easy to find images of them, as well. I enjoy building them and they have added visual impact to the layout.
SEPTEMBER 2013
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