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. [1] . It is the most powerful diesel–electric locomotive model ever built on a single frame, having two 16-645E3A diesel prime movers. [2] .

Union Pacific has retained only one of its 47 Centennial diesel-electric locomotives, No. 6936. The Centennials were the largest diesel-electric locomotives ever built. Actually comprising two engines on one frame, they delivered 6,600 horsepower.

Dec 16, 2024 · The DDA40X was an experimental, high-horsepower diesel locomotive designed by Electro-Motive for Union Pacific during the late 1960s. It received its classic nickname as the "Centennial" to commemorate the 100th anniversary of the completion of the Transcontinental Railroad at Promontory Point, Utah.

Jan 15, 2003 · Weighing in at 270 tons, the DDA40X was labeled as 'The World's Largest and Most powerful Diesel Electric Locomotive'." All of the Centennial units were equipped to operate at 90 miles per hour, using EMD's standard high speed 59:18 gear ratio.

Union Pacific 6936 is an EMD DDA40X locomotive built for the Union Pacific Railroad (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 …

In 1969 UP purchased the very largest and most powerful diesel ever built, the DDA40X, with 6600 HP provided by two diesel engines (prime movers) mounted on one frame,

Jan 29, 2025 · To meet the challenge, Union Pacific has been searching for the ideal road locomotive for nearly a century. In the 1940's, they had the 4-8-8-4 Big Boy steam locomotives.

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 16-645E3A diesel prime movers.

Union Pacific 6916 is a DDA40X diesel locomotive built for the Union Pacific Railroad. It now resides in the Eccles Rail Center at the Utah State Railroad Museum in Ogden, Utah.

Built exclusively for Union Pacific by EMD between 1969 & 1971, the DDA40X Centennial locomotives were the modern equivalent of the railroad’s famed Big Boy steam locomotives. These massive 98-foot double-engine diesels were UP’s mainstay hotshot power for …