model:

builder:

built:

builder number:

cost when new:

prime mover:

horsepower:

operating weight:

length:

max. speed:

DDA40X

GM Electro-Motive Division

September 1971

35520

2 - 645E3A - 16 cylinder each

6600

545,432 lbs.

98 ft. 5 in.

90 MPH

The Union Pacific, which formed one half of the first transcontinental railroad, was  famous for its large, powerful steam locomotives, culminating with the grandest of them all: the fabled Big Boy.  In the diesel era, that tradition continued as UP continued to field the mightiest locomotives possible.  In 1969, the railroad began operating the largest and most powerful diesels ever built: the DDA40Xs.

A custom model for UP, these 270 ton, 98 foot long monsters produced 6600 HP from two 16 cylinder diesel engines.  They were capable of 90 MPH and averaged 100,000 miles per year before 1980.  The builder, the Electro-Motive Division of GM, also used them as prototypes for new electrical systems and other advances which would surface in their new locomotives starting in 1972.

The DDA40Xs were called "Centennials" in honor of the 100th anniversary of the Golden Spike Ceremony, May 10, 1869, which completed the transcontinental railroad. In all, 47 units, numbered 6900-6946, were built from May, 1969 to Sept, 1971.  Those who operated the locomotives also called them "Big Jacks".

By 1986, new model diesels and an economic downturn led to the retirement of the Centennials.  The UP retained one unit, 6936, for its historic fleet and donated 12 others for preservation.  Our 6946 was the last Centennial ever built and the first donated.  The unique history and awesome size and power of a Centennial has garnered it iconic status in the railroad world.  Even as new locomotives boast 6000 HP from one engine, the Centennials reside in a class all their own.