I was looking over the Steel Town article in Run 261 and on page 50 paragraph three, I came across the following blanket statement: "For example, one minor difficulty with Lionel FasTrak is that the roadbed stands unrealistcally high."
I hope none of you take that statement to heart. The height of roadbed along a right-of-way can and does vary, many times to a great degree. While yard tracks may be flat, out on the road I have seen roadbeds where even my 6'2" frame had to reach up just to grab the bottom of the strirrup. Keep in mind that over the years mainlines need upkeep and that means new ballast. New ballast means the track is getting higher a little bit each time. The side of track next to rivers and slopes will tend to be higher than the side away from the river or next to the rock wall of a cliff.
So, while FasTrak roadbed may be too high for a yard, it most definately isn't always like that for a mainline. Vary your ballast height to meet your own needs. Mr. Riddle's way of doing that with foam board is one way to get it done, especially in a yard or engine terminal where the surrounding ground is mostly even with the tie butts.