Union Pacific 6936 is an

EMD DDA40X The EMD DDA40X is a 6,600 hp (4,943 kW) D-D locomotive, built by EMD from 1969 to 1971 exclusively for the Union Pacific Railroad. It is the most powerful diesel-electric locomotive model ever built on a single frame, having two 16 ...

locomotive A locomotive or engine is a rail transport vehicle that provides the motive power for a train. If a locomotive is capable of carrying a payload, it is usually rather referred to as a multiple unit, motor coach, railcar or power car; the ...

built for 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 ...

( UP). Previously a part of UP's heritage fleet, 6936 was for several decades the last remaining operational "Centennial" type, and thus the largest operational diesel-electric locomotive in the world. It is now owned by the Railroading Heritage of Midwest America in

Silvis, Illinois Silvis is a city in Rock Island County, Illinois, United States. It is part of a larger metropolitan area known as the Quad Cities. The Quad Cities Metropolitan Area is situated across four counties in Illinois and Iowa. It is located four miles ...

, who plans to return the locomotive to operation.

History

Service with Union Pacific

Built in January 1971, the UP classifies No. 6936 as a DD40X rather than a DDA40X as indicated by the model designation on the cab of the locomotive. It served in revenue service over the next decade and into the mid-1980s across the

Union Pacific 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 Pac ...

system. UP 6936 made its last regular freight trip on May 6, 1985. It went on to become a part of the railroad's

excursion An excursion is a trip by a group of people, usually made for leisure, education, or physical purposes. It is often an adjunct to a longer journey or visit to a place, sometimes for other (typically work-related) purposes. Public transportation ...

fleet. The locomotive's last

with UP was in 2015, when it helped the UP's trio of

EMD E9 The E9 is a , A1A-A1A passenger train-hauling diesel locomotive built by General Motors' Electro-Motive Division of La Grange, Illinois, between April 1954 and January 1964. 100 cab-equipped A units were produced and 44 cabless booster B units ...

units at the annual Cheyenne Frontier Days event. It was last used on July 12, 2016, when it helped to test UP 844, a

steam locomotive A steam locomotive is a locomotive that provides the force to move itself and other vehicles by means of the expansion of steam. It is fuelled by burning combustible material (usually coal, oil or, rarely, wood) to heat water in the loco ...

being returned to service. Its

dynamic brakes Dynamic braking is the use of an electric traction motor as a generator when slowing a vehicle such as an electric or diesel-electric locomotive. It is termed " rheostatic" if the generated electrical power is dissipated as heat in brake grid ...

were used to simulate a load while being pulled. After the tests, it was placed into storage at the roundhouse in Cheyenne. The current operating condition of No. 6936 is unclear. As of 2017, a page posted on UP's website said the locomotive "now travels on occasion as part of the UP Heritage Fleet." But a page posted in 2019 does not describe No. 6936 as operational.

Accidents

In November 2000, UP 6936 collided with a dump truck at a grade crossing in Livonia, Louisiana. The accident killed a railroad employee riding in the nose section and the driver of the dump truck. The unit was stored in

North Little Rock, Arkansas North Little Rock is a city in Pulaski County, Arkansas, across the Arkansas from Little Rock in the central part of the state. The population was 64,591 at the 2020 census. In 2019 the estimated population was 65,903, making it the seventh-mo ...

, until damage to its nose could be repaired.

Acquisition by RRHMA

In April 2022, Union Pacific announced that 6936—along with

Union Pacific 3985 Union Pacific 3985, also known as the "Challenger", is a four-cylinder simple articulated 4-6-6-4 "Challenger"-type steam locomotive built in July 1943 by the American Locomotive Company (ALCO) of Schenectady, New York, for the Union Pacific Ra ...

, Union Pacific 5511, and several other pieces of equipment stored at the Cheyenne roundhouse—were to be donated to the Railroading Heritage of Midwest America, with plans to return the locomotive to operation. In November of that same year, UP moved 6936 and the rest of the donated equipment to the RRHMA's large shop facility in Silvis,

Illinois Illinois ( ) is a state in the Midwestern United States. Its largest metropolitan areas include the Chicago metropolitan area, and the Metro East section, of Greater St. Louis. Other smaller metropolitan areas include, Peoria and Rock ...

. As of 2023, No. 6936 remains stored, awaiting a future return to operation.

References

External links

* , maintained by

{{UP Giants 6936 D-D locomotives Electro-Motive Division locomotives Diesel-electric locomotives of the United States Standard gauge locomotives of the United States