Union Pacific 6936

Union Pacific 6936 is an EMD DDA40X locomotive owned by Union Pacific Railroad (UP) as part of its heritage fleet. It was for several decades the last remaining operational "Centennial" type, and thus the largest operational diesel-electric locomotive in the world. Today, UP 6936 is stored in Cheyenne, Wyoming, at the roundhouse that hosts Union Pacific's steam program in preservation.

Union Pacific 6936
UP 6936 EMD DDA40X.jpg
UP 6936 photographed near Watseka, Illinois, pulling a business train.
UP 6936 as it appeared before the 2000 collision.
UP 6936 as it appeared before the 2000 collision.
Type and origin
Power typeDiesel-electric
Build dateJanuary 1971
Gauge4 ft 8+12 in (1,435 mm) standard gauge
Safety systemsLeslie S3LR
OperatorsUnion Pacific
DispositionStored in Cheyenne, WY. Believed to be operable.

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.[1][2] It served in revenue service over the next decade and into the mid-1980s across the Union Pacific system. UP 6936 made its last regular freight trip on May 6, 1985. Since then it has been part of the railroad's excursion fleet.

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, until damage to its nose could be repaired.[3]

The locomotive's most recent excursion was in 2015, when it helped the UP's trio of EMD E9 units at the annual Cheyenne Frontier Days event. It has not been used since, except on July 12, 2016, when helped to test UP 844, a steam locomotive being returned to service. Its dynamic brakes were used to simulate a load while being pulled.[4] After testing was complete, it was returned to 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."[5] But a page posted in 2019 does not describe No. 6936 as operational.[6]


  1. ^ "UP 6936". www.rrpicturearchives.net.
  2. ^ "Diesel-Electric Locomotives". www.up.com.
  3. ^ "Wreck damaged UP 6936 sitting in North Little Rock, Ark, December 7, 2000". TrainWeb. Retrieved June 8, 2019.
  4. ^ "UP: Locomotive No. 844 Makes First Return Journey". Union Pacific Railroad. July 13, 2016. Retrieved June 8, 2019.
  5. ^ "Timeline | History of Union Pacific". web.archive.org. 2017-02-23. Retrieved 2021-05-24.
  6. ^ "UP: Centennial DD40X". web.archive.org. 2019-07-19. Retrieved 2021-05-24.

External linksEdit

  Media related to Union Pacific 6936 at Wikimedia Commons