Union Pacific Doubles Down

Pan shot of Union Pacific DD40X #6936 at Duncan, Nebraska on 24 April 1994. (Paul DeLuca photo)


American Locomotive Co. (Alco), Electro-Motive Divion of GM (EMD) and General Electric (GE) were all touting the merits of the twin-diesel locomotive in their mid-1960s sales catalogue. The horsepower race was at full stride, with Alco's Century 855 in the lead, at least initially in terms of its 5500-hp rating. However, they were not the first to market that honor belonged solely to EMD and its 5000-hp DD35 demonstrator team. Soon afterwards, a trio of new Union Pacific U50s arrived from Erie. The First of UP's cab-less double diesels from EMD arrived in June 1964. The GEs and Alcos rode on four two-axle, span bolstered trucks, while the EMDs featured a pair of four-motor trucks. EMD's cab-equipped DD35As arrived in 1965 and marked the last of the initial wave of double diesels.

Round two of the double-diesel era began in April 1969 with delivery of new 6900 series DD40AXs; the 6600-hp units were just-in time to help UP mark the 100th anniversary of the Golden Spike -- hence the name "centennials." GE's newest twin-diesel -- U50C -- began shipping fron Erie during October of the same year. The new model was equipped with C-C trucks rather than two pair of two-axle trucks.

At the heighth of the double diesel craze, the UP roster consisted of:

  • 27 DD35s (includes two ex-EMD demonstrators)
  • 15 DD35As
  • 47 DD40AXs
  • 23 U50s
  • 40 U50Cs
  • 3 C855s (2 A-units and 1 B-unit)

XXXX * * * Photo Gallery * * *

ELectro-Motive Division (EMD) Models

DD35 #75B at Kansas City on 29 June 1969

John Stubblefield photo (R. Craig collection)

DD35A #75 ay Salt Lake City, Utah in April 1968

Keith Ardinger photo (R. Craig collection)

UP #6944 after restoration work at Altoona on 22 May 2015

Casey Thomason photo

UP 6941 at Verdemont, CA on 24 April 2008. (Craig Walker photo)

General Electric (GE) Models

UP #90399 [an early "Double Diesel"] :-)

Don Ross photo on 9 August 1968

U50 #45 at Council Bluffs, Iowa on 21 April 1974

George Cockle photo(R. Craig collection)

U50C #5008 at Clyde Yard (Chicago), Illinois on 29 May 1970

R. Craig Rutherford photo

U50C #5021 at Clyde Yard (Chicago), Illinois on 30 May 1971

R. Craig Rutherford photo

American Locomotive Co. (Alco) Models

C855 #60

RR "Dick" Wallin photo (R. Craig collection)

C855B drawing by Jean-Denis Bachand


Format by: R.Craig New: 1 July 2022

Reference sources:

  • Union Pacific Diesel Locomotives by Don Strack
  • Union Pacific Motive Power Review (1968-1977) by F. Hol Wagner, Jr. and James Watson

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