The GE U50 was an eight-axle,

diesel-electric locomotive A diesel locomotive is a type of railway locomotive in which the prime mover (locomotive), prime mover is a diesel engine. Several types of diesel locomotives have been developed, differing mainly in the means by which mechanical power is conv ...

built by

GE Rail GE Transportation is a division of Wabtec. It was known as GE Rail and owned by General Electric until sold to Wabtec on February 25, 2019. The organization manufactures equipment for the railroad, marine, mining, drilling and energy generation ...

. They were twin-engined locomotives, combining two

diesel engine The diesel engine, named after Rudolf Diesel, is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression; thus, the diesel engine is a so-call ...

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The U50 rode on four two-axle

trucks A truck or lorry is a motor vehicle designed to transport cargo, carry specialized payloads, or perform other utilitarian work. Trucks vary greatly in size, power, and configuration, but the vast majority feature body-on-frame construction ...

, grouped in pairs linked by

span bolster Span may refer to: Science, technology and engineering * Span (unit), the width of a human hand * Span (engineering), a section between two intermediate supports * Wingspan, the distance between the wingtips of a bird or aircraft * Sorbitan ester ...

s, giving a

wheel arrangement In rail transport, a wheel arrangement or wheel configuration is a system of classifying the way in which wheels are distributed under a locomotive. Several notations exist to describe the wheel assemblies of a locomotive by type, position, and c ...

of B+B-B+B. The trucks and bolsters were re-used from scrapped UP turbine locomotives built by GE during the 1950s. The U50 is sometimes inaccurately referred to as the U50D, a back-formation from the U50C name given to the six-axle units. The name is incorrect and was never used by the manufacturer or the railroad. The U50 did not ride on D trucks in any case. It is also sometimes referred to as the U50B, but this is incorrect as well. The U50 was built in response to the

Union Pacific Railroad The Union Pacific Railroad , legally Union Pacific Railroad Company and often called simply Union Pacific, is a freight-hauling railroad that operates 8,300 locomotives over routes in 23 U.S. states west of Chicago and New Orleans. Union Paci ...

's requirement, issued in the early 1960s, for a 3-unit locomotive intended to replace the turbines. The design was effectively two U25B locomotives on a single frame; each

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 The Southern Pacific (or Espee from the railroad initials- SP) was an American Class I railroad network that existed from 1865 to 1996 and operated largely in the Western United States. The system was operated by various companies under the ...

in May and June 1964. Other locomotives built to this requirement were the

EMD DD35A The EMD DD35A, also known as the EMD DDA35, was a diesel-electric locomotive of D-D wheel arrangement built by General Motors Electro-Motive Division exclusively for the Union Pacific Railroad. They were a cab-equipped variant of the previou ...

and the

ALCO Century 855 The ALCO Century 855 was a model of diesel-electric locomotive built in 1964 by the American Locomotive Company for the Union Pacific Railroad. The locomotive was notable for being ALCO's most powerful diesel-electric locomotive and, at the ti ...

. 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. The Union Pacific was more satisfied with their three, and ordered 20 more. A batch of 12 were delivered between July and September 1964, while a final eight were built May through August 1965. They were numbered #31-53. UP #52 was delivered with a Cummins PT fuel system and rated at 5,600 horsepower. The #52 had a standard fuel system installed in October 1966 and was rerated to 5,000 horsepower. Twenty of the Union Pacific U50s were withdrawn from service in 1973 and 1974 and traded-in to GE for U30Cs. The last three Union Pacific units remained on the roster until April 1977. The Southern Pacific's three survived in service until 1977. All of the Union Pacific "U-Boats" & Southern Pacific "Baby Hueys" were sold for scrap by 1977.

References

* * * * Mentions earlier UP GE purchases also. * * {{GE diesels Diesel-electric locomotives of the United States U50 Union Pacific Railroad locomotives B+B-B+B locomotives Railway locomotives introduced in 1963 Scrapped locomotives Freight locomotives Standard gauge locomotives of the United States

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References