Little History:

The U50 was built in response to the Union Pacific Railroad's requirement, issued in the early 1960s, for a 15,000 hp (11,200 kW) 3-unit locomotive intended to replace the turbines. The design was effectively two U25B locomotives on a single frame; each diesel engine and generator powered only the two trucks at the same end. Three were delivered to the UP in October 1963, and three to the Southern Pacific Railroad in May and June 1964. Other locomotives built to this requirement were the EMD DD35A and the ALCO Century 855. The Southern Pacific kept the three but did not order any more. They were kept on the roster until the late 1970s, but were often sidelined. While the UP's units were nicknamed ''U-Boats'', The SP's units gained the nickname ''Baby Hueys'' from the cartoon character of the same name. Original numbers were #8500-8502; they were later renumbered #9550-9552 and renumbered again to #9950-9952. Southern Pacific's three units differed from the Union Pacific U50s by having a cab door and headlights in the hood beneath the front windows.


Original Design.