Monday, November 25, 2013
Some time ago, I noticed that the wooden structure under my hanging train set was beginning to buckle under the load. Once it became apparent that the condition was getting worse, then it was time to plan its replacement. The previous design used 3/8 plywood on 2 2x4 studs. The landscaping was made of a collection of whatever materials I had on hand, mostly blocks of wood and wadded up newspaper. Add in some chickenwire, and a thick layer of plaster cloth and you get a lot of weight very quickly. This heavy, patchwork construction was more than those 2 2x4’s could handle, and I was very nervous about walking under when it was retracted to the ceiling. And the thought of parking under it to work on the car made me have bad dreams! Looking around at the materials available to me, and reading the blog posts and experiences of many other modelers, I quickly came to the conclusion that it would be best to use steel studs and foam boards. Design took a little while, eventually leading me to use Google’s SketchUp tool to make a rough mockup. The 3D models here turned out to be fairly close to what got built. Its dimensions are 5’ x 8’, a little larger than the wooden layout from before. This one will also eventually have side panels to provide a nice even trim/border. That should look very nice when complete.
The differences from the final product are mainly the diagonal cross brace which was not needed, and the cable lift points that were moved outside the frame body on a couple long of pieces of angle metal. I did find that putting forth the effort to make this model in the SketchUp tool really made me think about structure and load bearing and such. I am not an engineer by any means, but I think this system will work out pretty good. Once the basic steel structure was built, and the two layers of 1” foam board were glued onto it, I could still easily pick the whole structure up and hold it with one hand while moving my sawhorses around with the other.
In the following pictures, you will note two types of foam in use. The white foam ramps are Woodland Scenics 4% grade kits. And the pink foam boards are 1” Foamular brand insulation from Home Depot. So far the Foamular material is pretty easy to work with. I have been shaping it with a small keyhole saw, and a “cheese grater” rasp of the type that is used by sheetrock finishers. It should accept paint easily, and being able to carve and work the textures with simple hand tools makes this an art project as much as it is an engineering project.
The track plan is pretty simple, 4 loops in a gigantic oval. Most of the interesting bits of the track plan on this layout involve elevation changes. The climb up the hills to the small town near the red trestle bridge, and (not visible yet) the elevated train station on the opposite side of the layout from the existing overhead station. The other feature that will not be visible until well into the project is a suspension bridge! Actually a “cable stayed bridge”, it will span 2.5 to 3 feet from the end of the ascent across the valley to the hilltop town. Under that long span at ground level will be a small industrial yard and some container freight handling equipment. The current plan is to build the bridge from a single piece of flextrack, and use balsa to build the bridge deck around it. The weight of the bridge, as well as the weight of engines and rolling stock crossing it will actually be held by the cables, just like the real thing! Very cool if it works, and still fairly nifty if it fails and I have to go back to the drawing board….
More pics later, as progress is made.