One of the first undertakings of the United States Railway Administration (USRA), established during WWI to regulate the railroad industry during the war, was the development of locomotive and rolling stock designs that could be shared by the numerous railroads throughout the country. This "common design" program was quite successful in streamlining production, and many USRA locos ended up being used well after the war was over. Of the twelve designs created, 233 of the Heavy Mikado type were built. Some of them are still service today, though only for tourist or railfan trips.
 
The models are produced in two engine numbers for four different roadnames, plus an unlettered unit. Each engine features a graphite or silver colored front smokebox and firebox; a rear of the tender equipped with fully-automatic, magnetic knuckle coupler; improved electrical pick-up capability; and several details (such as handrails, whistle and tender ladder) that need to be installed by the modeler. Models are less traction tires, but a traction tire driver conversion is available as item #381-11604, sold separately.