Colleagues,The NP Bridge gang has spent the last few sessions at the "pooter" working on another widowmaker a little further up the hill from the "S" trestle.Perhaps a little explanation before you gaze upon the image attached. Essentially, these trestles are built from the top down, and thanks to the immense help of Ron Picardi in producing transparent textures, what you really see is a ton of organised textures - organised to look like a trestle, and a little bit of structural wood. I use TSM to build these things, and what I dod first on a timber trestle is fit the deck to the gradient & curve. In this case the inclination angle is 2.25 degrees, which is constant for all pieces, and the curvature offset ranges from zero (there are two 7M straight pieces between the dynamics) to 2.75 degrees, with each deck piece between 15ft. in length at the outside. Before I started on the "S" trestle, I created 5 post Bents, with textures for cross bracing, in 15ft. increments from 15 to 120ft. in height, and also cross brace textured polygons in 1, 2, 3, 4, 5, 6, 7, & 8 tiles per polgon verticle. The long straight portion consists of a single polygon on each side that is tiled in both axes.
The deck is complete, and abutments are in place, so now it is just a matter of filling in with support bents of appropriate length, and cross brace textures.
Since this type of trestle is simply piles driven into the ground, there is no need for concrete footings as would be the case with a steel structure.
This monster is on a 90M curve, which figures to 19.4 degrees of curvature, pretty sharp. It is the sharpest curve on the branch. Not having a profile, I just digitized over an aerial of the area. 2--6-6-2s were used on this line from about 1905 on, and these were rated at about 400 tons - cars of the day averaged 40 tons or less. By the end of steam, 2-8-8-2s were used and these were rated at 700 tons IN GOOD WEATHER, considerably less in snow and rain.J. H. Sullivan
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