I have bought an old-time flat car, and was quite happy with it. It had a cast frame so it was heavy and tracked well. The wheels were plastic, but could be easily replaced with metal wheels. I think all of the truss-rod old-time cars use the same frame and should run equally well.
I converted the car to narrow gauge by both narrowing the deck and filing some off the frame. It still tracks well, but the details are a little generic.
I can't say much about the other cars, but I hear the passenger cars are good.
Kevin
