zoom_in Click to enlarge

EMD DDA40X

▲ ▼

description EMD DDA40X Overview

The EMD DDA40X is a diesel-electric locomotive built by the Electro-Motive Division of General Motors exclusively for Union Pacific Railroad. Produced from 1969 to 1971, each unit combined two diesel engines on one frame and delivered 6,600 horsepower through eight traction motors. Union Pacific called the locomotives Centennials because the first units entered service during the railroad's 1969 centennial celebrations, and they were used primarily on heavy freight trains.

help EMD DDA40X FAQ

How powerful was the EMD DDA40X?

The DDA40X delivered 6,600 horsepower from two diesel engines mounted on one frame. Union Pacific used it as a diesel-electric locomotive for heavy freight service. [Union Pacific](https://www.up.com/about-us/history/heritage-fleet/centennial)

Why was the DDA40X called the Centennial?

Union Pacific introduced the class in 1969 to mark the railroad’s centennial celebration. The nickname also connected the locomotives with the 100th anniversary of the completion of the first transcontinental railroad. [Union Pacific](https://www.up.com/about-us/history/heritage-fleet/centennial)

How many DDA40X locomotives were built?

EMD built 47 DDA40X locomotives for Union Pacific between 1969 and 1971. They were numbered 6900 through 6946 and were built exclusively for Union Pacific. [Union Pacific](https://www.up.com/about-us/history/heritage-fleet/centennial)

How did the DDA40X differ from a conventional diesel locomotive?

Instead of one prime mover, it used two 16-cylinder diesel engines in a single long locomotive body. Union Pacific operated the class in fast freight service until retirement in 1984, while one example remains in the railroad’s heritage fleet. [Union Pacific](https://www.up.com/about-us/history/heritage-fleet/centennial)

swap_horiz

Looking for EMD DDA40X alternatives? Compare top competitors ranked & scored

arrow_forward