If I understand you right, in my scenario of a 4x4 base, i would make 2 cuts for a middle section as wide as my highest part of the layout, attach a piece of plywood to the top when the layout is folded, and pieces in the sides to finish the box. What if I created some hinges on the sides that start under the layout that swings nearly 360 degrees that would create the top piece? Whould such a thing be possible instead of a loose piece for the top?.
Overall, what you describe is kind of what I was wishing to accomplish, I guess I just didn't see how to get it done it properly. I might have to replace the side pieces which are 2x4 to something smaller for weight purposes, but it sounds pretty good. Let me know if I got it down.
Yes, you have the idea right.
The hinged flap idea for closing in the top of the "U" portion is really good. Not sure you can get hinges that rotate almost 360 degrees, but IIRC there is a hinge that, oddly enough, is "U" shaped which would allow it to swing into position to close the top. Side pieces can be as simple as cardboard, foamcore board or even lightweight luaun plywood. Depends on how much protection the sides will need in storage.
One thought to keep in mind. When you fold up the wings into the U shape, you will have to keep sufficient space clear at the hinged area to avoid hitting the scenery. One simple trick is to have no elevated scenery on the center section, such as a river valley or farm field. That way, scenery on the wings just folds over the center section with no interference.
Yes, I would definitely use smaller lumber! 3/8" plywood with 1"x2" frames should be strong enough. Screw them together using glue and it should hold up well.
Thinking a little further along, if you make each section (center section and both wings) as independent box frames of 1x2's with 3/8" plywood top, the hinges could attach on the frame instead of the plywood. Much stronger there and can be disguised better by recessing the hinges into the frames.
This sounds like a really interesting project. I have some On30 equipment that I bought to use under the Christmas tree. I was originally planning on using 2" foam for the base. The tree would sit either on top of the foam or in a hole cut out of the middle of the foam. Now you have me thinking that a folding box arrangement would be better since I, too, will be storing the layout for most of the year. I hadn't planned on any real scenery; I just wanted a train at the base of the tree to compliment the N scale train that's IN the tree. I chose On30 because I can use 15" curves to keep the layout small enough to fit under the tree. A folding U layout like you're contemplating would allow me to add some scenery. I'm liking this idea better and better!
If you get started on this, make sure you post pictures of your progress. If I get started on one for myself, I'll be sure to post my progress pictures, too.
Darrell, quiet...for now