The Horizontal motor, and drive shafts, from the fuel tank, are much different, from the basic, two vertical can motor drive system, most are familiar with. One of the last 6 axle offerings was the SD9. A very nice model. IMO, Mike CT
Edit/Add: Also note, that even though this model is three rail, the wheel flanges are not proto-typical three rail (large flanges), that inhibit de-rail, on tight curves. IMO, Mike CT.