Woodland Scenics' foam track-bed comes on a 24-foot continuous roll that makes it easy to work with. This should be enough to lay most of an exterior mainline for a model railroad or train system. All standard HO gauge track should fit on top of the foam. Foam track-bed can replace cork material on any HO layout. It won't crack from humidity and it resists the growth of fungus. The soft material will also help to deaden the sound of wheels crossing over rail joiners.