what vintage?
These were sold for quite a few years with some changes is the parts over time. The first ones made had brass driver tires, open frame motors and gears that needed a lot of work.
I built one of the early units, and used a NWSL regear kit. and after a lot of work got an ok running unit. unfortunately I loaned it out, and lost contact with the individual who had it, it is out there somwhere, with a cabbage stack, and lettered for the state line RR.
I built another that was a later version of the kit, and had nickel silver driver tires. by that time the stock gearing was much improved, and a much better motor was provided. I built the second one with the stock gearing, and it runs as well as any HOn3 rod engine I have ever seen, very smooth. I did some surgery to it to lower the boiler, which improves the look of this locomotive, Mechanically the only alteration I made was to add electrical pick up to the insulated drivers and the insulated tender trucks, which made a big improvement in the locomotive's.
Building from piles of parts, one might get pieces from each version, and might have compatibility issues.
I looked through my pictures and didn't see a picture of this massive beast, I'll have to fix that.
http://www.zealot.com/forum/showthread.php?t=167339&page=4
there are some photos of my 2nd MDC 2-8-0 on page four of my Hon3 locomotive shops thread, which covers some of my modifications, and painting techniques.
Bill Nelson