I wanted to add a little depth and contour to my layout but not having any long runs I was worried about slope, so I abandoned my original plan to have one track cross the other. Instead, I just raised one track the height of the 2" pink foam board and ran inner loop a bit higher than outer. I created approx. 6' of retaining wall around the curve by buying a 12"x12" piece of small block tile from Lowe's (about $16) and glueing to the curve. I keep adding lynchen and other effects as I go along.