I have a endless suppy of foam to use. From 1/2 inch to 5 inch thick pink and blue kind. Has anyone laid n-scale track on just foam not wood.And to make the track raiseup too.
Our model railroad group (ho scale) uses only foam for our modules, we do not lay it on top of plywood. We use water base contact cement to glue the foam rubber (the type used for automobile headliners) we use for roadbed to the foam base. We use the same glue to put down the track, weighing it down and holding it in place with lead weights. Paper is put under the movable parts of switches when glueing the track so they will still operate. This has worked well for many years and withheld the rigors of moving, setting up and tearing down and the shows we do (at least 5 a year). If you have any further questions contact me directly at: CRLD_LIPPINCOTT@MSN.COM and I will put you in contact with another member of our group who can give you more technical information.
There’s a thread on the Atlas forum that may be of interest:
http://forum.atlasrr.com/topic.asp?TOPIC_ID=23507
IMHO, foam on top of plywood is the best of both worlds.