I was surfing the one day and I found a nice little program called Terragen. I t's a utility to build edit terrain with. I have been playing with it for a few days and I think it might work very well for building track terrain. I used to build the terrain for my new track and it came out pretty good.
This program works a lot like the random terrain feature in traxx, but it has a few added editors to use to wedit the terrain a lot better
The only thing is that you have to export the terrain as a .raw file the copy like you would do a normal .bmp.
You can get it at: http://members.xoom.com/reosped/teragen.zip
I will also be posting it on my utility page soon.