My preferred subsurface for layouts is plywood; however, cork road bed is a must, in my opinion, on foam too. Although cork must be glued to foam, it can be stapled to plywood which is faster and easier. When used on foam, flex track can be laid using nails which will embed securely in the cork to hold until ballasting is complete and dry. This product comes with beveled edges and a split down the middle. It is intended that the cork be split apart (it's very easy) with each half being glued or stapled against the track line. Even tight radii are easily circumnavigated with this product in this manner. I prefer to use only half pieces, centering them on the track line with the bevel turned down. This way the ballast forms the fall, not the cork. I think this creates a more natural looking fall along the edges of your track (see pictures). More ballast is used this way, but you make up the difference by using only half the cork.