Yeah, that's neat. This guy does some awesome work too. Damned expensive though.

I've been playing with NoLimits Roller Coaster Simulation lately. The editor is amazing, very CAD-like. Plus, there is a terrain editor which really opens the possiblities of design. Anyway, anyone who is interested in roller coasters should definitely check it out. Best simulator I've seen so far, and it's only $25.