I am scratch building an HO trestle using 18R Atlas. While I understand, well sorta’, that I won’t be matching prototype, I’m just trying to get something that will entertain my son, until he can join in a bit more. The track comes off a ledge at 5" height in the middle of an 18R curve, to a 6" straight and into another 90 degrees of 18R, all on the 5" tall trusses. From there it strightens and drops at about 2% grade. The non prototype part (will one part) is the trusses will be about 5 to 6 inches apart and joined by cross braces and the stringer on top.
My probelm is the curve in the stringers I’d like to put on top, (the trusses have a heavy top piece of 3/8 basswood, and I want the stringer to follow the curves and straight under the rails and ties). That is the stringer will follow the rails in arc and width spacing. I tried to use balsa 1/4 x 3/8 laying it on the narrow side, but can’t get enough curve out of it before it snaps. I figured basswood of that size would be worse. I did try to place small cuts on the inside of the stringer, but same result, snapped before I got enough arc.
I cut pieces 1/4x1/16 put about 5 together, bent then to shape and held with clamps and clothepins. When I had it right, I disassembled it and spread a lot of carpenters glue and clamped back together. It took two of these of course.
There is an easy way to get a curved trestle, and the bonus, if you like realism, is that this is the way the prototype does it. See the link below, and find the faint thumbnail with the pattern for a curved trestle deck. I did this for the trestle in the picture that follows.
Just to reinforce Selector, in a model, you could no doubt make it work, but in the “real” world there is no such thing as a curved stringer. Only straights set at a slight angle to each other, as per his diagram.
The reason is simple: a curved stringer, even if braced so it doesn’t flop over, would be far, far weaker than a straight one.
First of all, thanks for the suggestions, I’m going with multiple thin strips guled in a formed curve to match the acutal track that will be mounted on top of the stringers. The pictures and plans were a big help as well.
With all due respect, as I stated, this is not prototype, Pondini I truly appreciate your comments and your dedication to true modeling. (I am not posting pictures because every dedicated modeler would likely have a fit, for good reason.) I have researched a little, here and elsewhere, and quickly discovered, what I’m doing ain’t right, but I’m trying to put a lot stuff in a small space for my son’s entertainment. We’ll see if I can in fact “make it work” the jury is still out.
Thanks again for the posts, if I can get this layout up and running, maybe my next will be a little closer to prototype, I’m still pretty sure I’m not going to get the dinning room for the layout though, that’s pretty awesome.
