I have never owned one of these, but according to the MR review below this model consists of a custom plastic shell plunked on top of a standard Fleischmann chassis. This basic Fleischmann 4-6-0 mechanism has been around forever (in fact, it's still available today). Many of Fleischmann's various DB livery 4-6-0 permutations share certain similarities with this Rocky Mountain version, but none of them are exact duplicates. From what I've been told, the shell was custom-manufactured by Intermodel (Germany), imported by Rocky Mountain for a brief period of time, and then allowed to vanish from the face of the planet shortly thereafter. And although I've never actually owned one myself, I guess I can review the basic mechanism if nothing else.
The motor and driving wheels all live inside the tender, whereas all pick-up is derived from the six drivers on the locomotive (transferred back to the tender via wires). Four of the eight driving wheels on the tender come equipped with traction tires. The motor is a fairly large 3-pole / straight-wound affair that does a pretty good job of moving the thing around. Unfortunately, there isn't much subtlety to the throttle response- it starts off fast and quickly accelerates up to warp factor nine by the time you get into the meaty end of the throttle. Given the relatively small pick-up footprint (not to mention the primitive wheel wipers on the drivers), stalls and overall jittery behavior are a big problem. I've also run into problems with the worm not meshing properly with the worm gear (the end result being a lot of noise). Also, the metal drawbar seems prone to causing the occasional short-circuit.
So, the Rocky Mountain 4-6-0 is an interesting bit of N scale history (and definitely a collector's item), but given the shortcomings of the Fleischmann mechanism, not anything you could really operate on a model railroad. FWIW, I've only seen two of these show up on eBay over the past decade, so the production numbers must've been quite small.
Grade: C (I'm assuming)
Reviewed: 9/72 Model Railroader ("Old-time steam locomotive varieties are still in short supply in N scale. This 4-6-0 is partially handcrafted from a standard Fleischmann mechanism. The model's new superstructure following American proportions has been constructed from polystyrene materials. The ready-to-run model is painted black with green cab which has red trim, and with brass and blue domes and gray smokebox. There is no exact prototype but the model effectively simulates a typical turn-of-the-century locomotive but with general dimensions closer to the proportions of the 1920-1930 era. The locomotive scales 39'-6" long, 15'-4" high, and 9'-3" wide over the cab. The width over the cylindars is 12'-0". The model is 66'-9" long over the tender end beam. The drivers scale 73" in diameter and the pilot and tender wheels scale 43" in diameter. The model uses a type of drive often utilized in Europe to power small-boilered locomotives. The engine is a free-wheeling dummy. Its wheels provide electrical pickup. The power unit and actual driving wheels are in the tendar. A small three-pole 12-volt DC motor drives eight tender wheels... The wheels are all mounted in a rigid frame; thus the trucks do not swivel. There is enough lateral play in the axles to allow the model to negotiate short-radius curves... The flanges are .040" deep and the check gauge is .312"... Our test sample ran smoothly but tended to have electrical contact problems... All tender drive wheels have friction treads, and the pulling capabilities of this model are astounding. Our sample pulled 16 85-foot passenger cars... this would be around 28 to 30 freight cars. Price: $65")