On18 Trestle

The Gap
Area2GoI have a gap that I will need to span for my On18 line. It starts from the cliffs on one side and will cross the gap to the other (duh). In this photo taken at an earlier point in the layout construction the red arrow shows where a trestle could go.

In this photo the opposite side is nothing but foam and the pier is at an early stage.

.. and later
Image1Rock has magically grown on the left side over the foam – distant mountains and printed trees glued to the background, a couple of structures – Critter Shed and Maintenance Shed in place and some trees and bushes to help blend into the background.

It was at this point that I decided to stop and start work on bridging the gap. The placement of the bent/support will depend on where the gap is bridged exactly. That along with the abutment on the left side will dictate any additional structures, scenery and such so .. on to bridge building.

Construction Trestle with Rail Stringers
OldRails2The following is from the “Engineering and mining journal, Volume 96” published November 15, 1913.

In the reconstruction of the line of the Pennsylvania R.R. at Rahway, N. J., the Keystone State Construction Co. has a considerable length of timber trestle in which the stringers are made of old rails discarded by the railway. These trestles, states Engineering News, are of two types, one used as a construction railway and the other as a filling trestle which is covered by the fill as it progresses.

The construction railway trestle is the heavier of the two and is shown in the accompanying illustration. It is made up of the usual framed bents with round log uprights and sapling braces and a squared 6×8-in. cap.

On this cap run the stringers, four old 100-lb. rails, in groups of two, spanning the 12-ft. opening between bents. These rails are spiked with standard railway spikes to the cap and are spliced wherever the breaks come with the standard rail splices with bolts only in the end holes.

The 3-ft. gauge construction track is built of old 70lb. rails spiked to 6×7-in. ties with an 8×9-in. tie dapped 2 in. over the stringer rails at the bents. These latter ties are bolted with 3/4-in. bolts to the bent caps, and this is the only fastening of the track to the bents or stringers.

In the filling trestle, the track rails also act as stringers. This track is of 3-ft. gage and is made up of old 100-lb. rails, spiked to 6×7-in. ties, which act merely as spacers between bents and as caps at the bents. The dirt train is backed onto the trestle and the cars are dumped at the edge of the fill so that no load but that of empty cars comes on the trestle. The ties and rails remain in the fill and form the construction track on the embankment.

Since the On18 would be very light (relatively) this would possibly be a nice, light trestle. I’m going to keep this in mind as I build the abutments.
Adding abutment support
startStarted roughing out a place for some 1×3 wood pieces for the abutments to attach to. I ran sheet-rock screws into the backs and getting ready to slap on some plaster and embed them into the rock walls.
supports.. and plastered into place. Sitting here this morning with my coffee and sleeping cats sprawled across my desk .. and wondering what to do next. Clean up the supports a bit, add plaster etc. to make it look like rock perhaps .. but what then? If I was going to make this a stone bridge then it would be relatively simply to add a 1×2 or something like .. for the track to ride on and build the bridge around that. If I continue with the idea of building a trestle then it will be more involved. Coffee first I think.
Seat Support
seatsupportI wanted a way to make the trestle removable. I think this would work.

The 1×3 piece of wood embedded into the rock will support the abutment. A smaller piece acting as the bridge seat would glue/screw to this. Note that it would actually serve as the bridge seat on the abutment. A 1/4″ sq. timber I call the seat timber would support the stringers and keep them off of the seat proper. Directly above the seat/seat timber is a piece of wood cut to fit between the stringers and the seat timber. Fit tightly together and glued well this would fix the end of the trestle into a solid piece. A couple of holes through this would secure the end of the trestle to the seat support .. the screws passing through the seat timber. From above it would appear to be a tie with only the heads of the two screws showing .. easily hidden.

seatsupport2Here’s the thing exploded. I believe that I can use this .. I’m going to give it a try anyway.


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