Hi!
I currently have 1/2 inch plywood, with 1x2 bracing on 16 inch centers with all exterior edges supported as well. Legs are 2x2 and connected with 1x2 and 1x4 and are spaced two to three feet apart. The result is very solid, and I will probably use the same on the new layout. My reason for the original question is that so many layouts I read about use 3/4 or thereabouts plywood.
Thanks,
Mobilman44
ENJOY !
Living in southeast Texas, formerly modeling the "postwar" Santa Fe and Illinois Central