As mentioned previously the landscape surface of my layout is going to be extruded foam, the pink stuff. In doing some tests I quickly found that there’s a significant amount of operating noise when putting the track (I’m using Atlas O) directly on the foam and rolling my heavyweight O gauge passenger cars on it. I ran a series of tests with the following materials, from top to bottom:

• K-Line Heavyweight Passenger Car
• Atlas O 40” Rigid Straight
• Woodland Scenics Track-Bed
• 2” Owens Corning Pink extruded foam
• 1/4” Lauan plywood
• L-girder benchwork topped with 1x4 joists

In short I found that by placing a sheet of 1/4” Lauan underneath the 2” extruded foam I was able to significantly reduce operating noise. Adding the Track-Bed improved upon this even further. Here’s what I found, in order of noisiest to quietest:

• Track, 2” foam – unacceptably noisy
• Track, Track-bed, 2” foam – unacceptably noisy - 1
• Track, 2” foam, 1/4” Lauan – not bad
• Track, Track-bed, 2” foam, 1/4” Lauan – very, very little added track noise

I don’t have the equipment to measure this scientifically, but my sense is that the foam amplifies whatever bass component there is to the train rolling on the track. Thankfully 1/4” of Lauan is enough to deaden that component back out.

In the interest of completeness, many people on the forums like to use Homasote boards as their sub-roadbed, but Homasote is pretty difficult to find in the southeast. If you’re thinking of doing a plain plywood sub-roadbed, Homasote seems to be worth looking into, but in my own small layout experience a plywood subroadbed was fine, even without the Track-Bed. Still though, I had cut the plywood to outline my track (like cookie-cutter style, but with the non-track areas removed, which was probably a mistake).

So I’ll be layering Lauan beneath my foam, which should give it a tiny bit of added stability too. Added expense and work, but worth it.