My layout has a long curve, inside a tunnel, running 2" higher than a double track curve. The outside of everything (i.e. the back of the mountain) is open, so I have access in case of derailments, but vertical clearance is limited. Wondering what people are using these days for support material that nobody is going to see. I need something thin and stiff. I'm considering 1/8" lexan from the hardware store, but would like to go even thinner. I will glue a vertical piece on the side to make it stiffer, and it will have several support piers between the two track layers.
