Housatonic Railroad 9935 was originally built for the Delaware, Lackawanna & Western as a model RS-3 diesel-electric locomotive by the American Locomotive Co. (ALCO) in Schenectady, NY. Built in April 1951, it was equipped with a Model 244, twelve-cylinder diesel engine generating 1,500 horsepower. Built as DL&W 910, it became Erie Lackawanna 1048 in 1960. When Conrail took over the operations of EL in 1976, it became 5264. Less than six months after takeover, Conrail retired the unit in October 1976.