Looking back over this build and the comments, one stands out as not answered? Matt asked about the drive?
Originally the frame was being built from scratch. I ended up cutting up a spare reject MTH GE Dash 8 frame and making it longer. So I meshed that into the answer.
The proper answer should have been the guts from a MTH Dash 8 that another person sold me at a different time. I had a pile of stuff at one time that I bought up from (3 or 4?) broken or gutted engines. The smoke unit was from a MTH 1 gauge Hudson that should be downsized. It doesn't need to smoke so good.
The trucks are stock MTH Dash 8 trucks with modified USA Trains SD70 side frames. They aren't perfect, but capture the look.
The fuel tank is modified and has a speaker and extra weight.
I never built the interior yet. Obviously no handrails or grabs yet!
Please remember that back when this started, there was no HONGZ forum!