The Union Pacific Challengers were simple articulated 4-6-6-4 steam locomotives built by American Locomotive Company for the Union Pacific. Union Pacific built 105 of these locomotives between 1936 and 1943. The Challengers were 122 ft (37 m) long, weighed 284,800 kg, and operated over most of the Union Pacific system, primarily in freight service. The excellent Challenger design allowed for increased speed on mountain grades compared to UP's previous articulated steam locomotives.
This BLI model is of the Class CSA-2 Challenger, commonly called an "early challenger". Our models have a post-1947 appearance, after the locomotives were renumbered from 3900 to 3800 series. We are offering three locomotive variations: four road numbers with the as-delivered front engine, four road numbers with a rebuilt front engine, and two road numbers with an integral cast cylinder front engine. All of our models are oil-burners with 19,000 gallon cylindrical tenders. We are also offering one painted but unlettered model of each variation, and we will build a small quantity of one model with all parts either varnished brass or painted brass. This model will have the as-delivered front engine.