My layout shelves are covered with 2" blue foam. As for roadbed, I had planned on glueing cork roadbed on that, but I got to thinking about another possibility. What if I glue the track directly to the blue foam and then carve the foam surface down, leaving the roadbed an integral piece of the foam? Regardless of which method I use, the foam is going to be carved up some anyway, just to eliminate the "flat as a board" layout syndrome. One concern would be noise factor. I have experimented with both methods, and didn't hear much of a difference in the sound levels. The cork roadbed method may be a bit easier and would require less carving of the foam. Any thoughts?