question about elevation and using foam

i had a question about using foam board

is it ok to have a wooden piece connect to a big peice of foam board that would be the base of the seanery?

let me put it another way, i had a thought if using foam as my base, but i would like a elevation change on my other side of my layout, differenyt thickness foam, i though i would run a track cookie cut out of ply wood to the next elevation. is there any problem of that thinking. because at the end of the wood would but up against the foam board at some point. should i go about this another way or is this ok? im worried of the two differennt materiels and expansion from the wood? i also cant find any pictures thus far on the web is it just not practical and its done another way? i have seen the riseres made of foam but do i have to use them?

I have done almost what you are explaining and I haven't had any problems mixing ply and foam. I glue them together with either white glue or PL-200/400 glues. I would recommend you to use some sort of risers or columns under the wood in order to reduce the risk of sagging wood.

thats what i was thinking that right where they meet there would be a riser for support to make it not move at all if possible .

I have done elevations a few different ways. One is to shave the foam into a ramp. In the photo below, the lower line uses this method. It raises an inch in the photo:



I now use Woodland scenics foam risers. These work well, but the foam is pretty light. I cut it in half when I do single lines. I cover it with cork for a good roadbed. But thin ply would also work. This method goes a long way for a smooth consistent rise in elevation.

Rob