Progress has been slow the past couple weeks. I was away from home for work, which didn’t help, but the bigger limiting factor right now is that I’m still waiting on the larger Atlas O curves I had ordered. The remaining switches arrived, which is good, but I have decided to make alternate arrangements for the curves. It’ll probably be another week before they get here. Even with my paper track stand-ins from the prior post, I’m reluctant to actually start doing much serious work beyond setting track on foam until the final pieces arrive.
I did spend some time tinkering with grade up two inches to the inner section of track. My Lionel CSX SD80MAC locomotive had some trouble getting up the grade on my prior layout, and with this new (much gentler!) grade I’ve been seeing the same thing. Except on this layout I can actually see what’s going wrong. Essentially the two outer inner axles on each of the trucks are the motorized wheels; the outer axles spin freely. When the grade increases too sharply, the locomotive gets stuck on those two outer sets of wheels. I’m also noticing that this locomotive’s pick-up roller, which has caused problems on the Atlas O switches in the past, is not negotiating the lovely O-72/O-54 switches very well. I think the best solution may be to look at limiting its downward travel. Tyler at Legacy Station told me some people use lash-ups to solve the problem (two or more locomotives working together) – the second locomotive pushes the first one over the trouble spot. An expensive fix to the problem, to be sure.
This weekend I began doing some preliminary work on the trestle bridge in the form of building the bent jig, shown at right. I’m pretty pleased with how it is turning out. Right now I’m using 3/8” dowels for the pilings, 3/8” square for the cap, and 1/4” square pieces for the sills and diagonal supports (not shown). The posts here are 16” long, which comes out to 64’ in O gauge, if my calculations are correct (16*48/12).
The next step is to do a stain test and if all goes well begin building some bents. I’ll also need to figure out how I’m going to build out the gorge that this trestle will cross. Building up (for mountains and so forth) is pretty easy; building down will be a bit different. I imagine I will end up building up from the floor. The L-girder benchwork is so easy that when I actually have to solve a benchwork problem, I’m not sure how to go about it. Access hatches will be another such problem to solve.
If you want to nerd out on trestle construction, there’s a pretty great post by Bob Hyman, Wooden Trestle Construction on the Rio Grande Southern Railroad.