I have 2 small conventional layouts. Both are hollow core door slabs on sawhorses. On the earlier one I tried weatherstripping on each tie (Marx 034 track) then an occasional screw. Works ok.
On the second one, I bought commercial foam roadbed from the bay pretty cheap. I glued it down with spray adhesive. I added the track, (marx 034 again), connected everything together with Marx track clips. Then I put a piece of two sided tape on one clip at each joint. The tape came from a cheap window winterizing kit. No nails or screws. Quietest layout yet. Been running trains on it since before christmas with no problems.