I was just scanning through some old MR's for track planning ideas and came across Bill Darnaby's articles on using foam for roadbed. Some interesting ideas...I think he is on the cutting edge (pun intended) with foam construction, though by no means the first or only modeler to use the techniques he's proposing. Sorry, can't remember what year this was in...been looking through so many lately. But a quick search on the Model Train Magazine Index should locate his articles. You may want to look them up if you are seriously considering using foam construction.
My learning curve with table top construction was this:
Atlas plan book layout built on a ply and lumber table top (built per their little blue book's instructions). Followed by, tearing this out and expanding the area, but still using table top as a base. Then using foam (the white stuff from packing around appliances's, etc.) as risers and 1/4" paneling as subroadbed with cork as roadbed. I soon discovered a major problem...I didn't have a drill bit long enough to run from beneath the tabletop up through the space and scenery base (more white foam with plaster/papertowels) to run wiring for lights, etc. Wiring the track wasn't that hard as the scenery hadn't been put in place yet. But once the mountains and hills took shape I realized the beauty of open grid construction for access purposes.
Galen
My learning curve with table top construction was this:
Atlas plan book layout built on a ply and lumber table top (built per their little blue book's instructions). Followed by, tearing this out and expanding the area, but still using table top as a base. Then using foam (the white stuff from packing around appliances's, etc.) as risers and 1/4" paneling as subroadbed with cork as roadbed. I soon discovered a major problem...I didn't have a drill bit long enough to run from beneath the tabletop up through the space and scenery base (more white foam with plaster/papertowels) to run wiring for lights, etc. Wiring the track wasn't that hard as the scenery hadn't been put in place yet. But once the mountains and hills took shape I realized the beauty of open grid construction for access purposes.
Galen