A Closer Look at Union Pacific’s Centennial Locomotives

EMD DDA40X
An EMD DDA40X (Centennial) on display at the Museum of the American Railroad in Frisco, Texas, on Dec. 29, 2016. (Photo by Todd DeFeo/The DeFeo Groupe)

Starting in May 1969, Union Pacific operated Centennial diesel-electric locomotives, famous as the largest diesel-electric locomotives ever built.

EMD DDA40X
An EMD DDA40X (Centennial) on display at the Illinois Railway Museum in Union, Ill., on July 16, 2016. (Photo by Todd DeFeo/The DeFeo Groupe)

Built by what was then General Motors Electro-Motive Division (EMD), the units — officially the EMD DDA40X — were nicknamed in honor of the centennial anniversary celebration of the completion of the continental railroad.

All 47 of the Centennial locomotives were delivered to UP by 1971. The locomotives were fully retired by 1984.

The locomotives were numbered from 6900 to 6946, in honor of the 1869 Golden Spike ceremony in Utah; the first of the locomotives attended the Golden Spike Centennial celebration.

The units were two engines built on a single frame. The locomotive weighed a stunning 270 tons, measured 98 feet long and delivered 6,600 horsepower.

A total of 13 Centennials remain. Most are on display in museums, including the Illinois Railway Museum in Union, Ill., and the Museum of the American Railroad in Frisco, Texas.

No. 6936 was assigned to special service in 1985 and remains in use by the railroad. Today, the locomotive is part of the UP Heritage Fleet.

Todd DeFeo
About Todd DeFeo 272 Articles
Todd DeFeo loves to travel anywhere, anytime, taking pictures and notes. An award-winning reporter, Todd revels in the experience and the fact that every place has a story to tell. He is owner of The DeFeo Groupe and also edits Express Telegraph and The Travel Trolley.