Peteski: I agree, 12 cm is a little short. My only excuse is that I was tired, and left off the zero. I didn't run that one through the calculator, just used 30 cm = 1 ft. My layout height isn't exact, or consistent, anyway!
Aikorob: That would be about 26 inches in N scale. Could work for a layout that's wheelchair-accessible. Has anyone ever built a permanent layout designed to be built and operated from a wheelchair?