@Hp289 posted:To be clear, even the 2" foam glued to the frame is loud? Or do you mean only the thinner foam?
My guess is the size would just produce a different sound. Don't get me wrong... It's not completely terrible, but it does produce more sound. Listen to this engine and track cleaning car.
At :20 it enters the 2" pink foam bridge. The rest of the layout is 1" foam on plywood.