Union Pacific 3985

Union Pacific 3985 is a four-cylinder articulated 4-6-6-4 Challenger type steam locomotive, built in July 1943 by the American Locomotive Company at Schenectady, New York, for the Union Pacific Railroad. It is one of only two Challengers still in existence and the only one to have run excursion service. Designed under Union Pacific chief mechanical engineer Otto Jabelmann, it weighs about 317 short tons in working order and has a calculated tractive effort of 97,350 pounds-force. It hauled revenue trains until 1957, was displayed at Cheyenne, Wyoming, and was restored by company volunteers to run again in March 1981, when it became the largest operating steam locomotive. It was retired from excursion work in January 2020, and in 2022 Union Pacific announced it would donate the engine to Railroading Heritage of Midwest America.