The GE U50C was the successor model to the earlier U50 design of the early 1960s. Once again this high horsepower locomotive's largest (and only) buyer was Union Pacific, which again requested a powerful, singular road-switcher in an attempt to reduce operating costs by employing less units per train. Perhaps the biggest difference in the two designs was the truck setup and overall weight, as the U50C was much lighter and shorter. While the model attempted to solve deficiencies experienced with the earlier U50, more arose with the new design. At the time, General Electric was simply not as proficient in manufacturing diesel locomtotives as EMD. Additionally, its prime mover was not on par with either of Electro-Motive's first two engines, the model 567 and 645. Interestingly, even though UP purchased more U50Cs than U50s it had scrapped or sold its entire roster after only a few years of service.
The GE U50C was requested only by Union Pacific and slightly different from the U50 in that it was meant for use in high-speed freight service instead of heavy drag assignments. The model still came equipped with two FDL model prime movers that combined could produce 5,000 horsepower. However, with less need for extreme pulling power the engines were of the 12-cylinder variety, not sixteen which were used on the U50. While the engines employed in the locomotive were essentially those used in the U25C, cataloged in 1963, the model's radiator design was more similar to the U33B/C due to the shorter length (making them much larger and more rectangular). The shorter length not only allowed the locomotive to be much lighter but it also featured a C-C truck setup instead of four, B-B trucks employed on the U50 which further reducing its weight.
While the U50 weighed in at 557,000 pounds (or 278 1/2 tons) the U50C weighed just 442,660 (or 221 1/3 tons). Even though this provided for reduced wear on the track structure the model was still plagued with numerous reliability problems due to several design flaws, particularly in the electrical system which caught fire several times. As it turned out the trucks were still not sufficient to handle the locomotive's weight, as cracks were later found. As it turned out, virtually every problem imaginable was happening with the U50Cs in service. Aside from the issues mentioned above the locomotives suffered from dynamic brake issues, oil pressure problems, and leaking water coolant. Despite all of these problems UP would eventually roster a fleet of 40 U50Cs, numbered 5000-5039 by the time General Electric had completed production in November of 1971.
At the time, GE was still fine tuning the development of its Universal series and models being released through the 1960s were regularly plagued with similar mechanical issues. However, the company's late model U-boats like the U30C, U33C, and U36C were much were reliable and carried many of the same components as its later "Dash 7" line. Still, at the time of the U50C's development EMD was simply a better locomotive builder not only due to the past successes of models like the GP38, GP35, GP30, GP9, GP7 and its entire cab series but also thanks to the powerful DDA40X "Centennial" model developed between 1968 and 1969.
While the locomotive (which followed up the earlier DD35A that also successful but nearly to the extent of its later counterpart) was an experimental design built solely for UP, and constructed at the same time as the U50C, it was so reliable that much of the fleet remained in service through the 1980s. Today, #6936 is still operational as part of UP's Heritage Fleet. In any event, because of the severe reliability issues the railroad had with the U50C all 40 were retired, sold, or scrapped by 1978 after less than ten years of service. Lastly, for more information about the locomotive and all of the builder's U-boat models please refer to the chart below.
For more reading about GE's U-boat line the book U-Boats: General Electric's Diesel Locomotive by author Greg McDonnell provides a complete history of the company's first production diesel models. Also, noted historian Brian Solomon has authored a number of books covering the history and background of GE's locomotives. Two, which provide for a general but thorough coverage include GE Locomotives and GE And EMD Locomotives: The Illustrated History. As with virtually all of Mr. Solomon's you can expect a well-written title with large, crisp, and sharp photographs.