Union Pacific EMD DDA40X “Centennial” No. 6936 powers a westbound engineering passenger special curving through Pinecliffe, Colorado, on October 4, 2001.

EMD DDA40X No. 6923 leads a westbound freight out of Cheyenne, Wyoming, in April 1984. Trailing the big “Centennial” is a pair of SD40-2s, and a large cut of stock cars behind the power.

A westbound Union Pacific train changes crews in front of the depot at Cheyenne, Wyoming, in April 1984. The train is led by an imposing UP DDA40X No. 6935. Delivered by EMD in 1969-71, UP Nos. 69... (more)

Union Pacific EMD DDA40X “Centennial” No. 6936 is serviced at UP’s North Yard at Denver, Colorado, on October 3, 2001. The unique locomotive will be powering an inspection train on the forme... (more)

A Roger Puta Photograph

Union Pacific’s EMD DDA40X “Centennial” No. 6936 powers a westbound engineering special at Crescent, Colorado, on October 4, 2001.

A westbound Union Pacific van train departs North Platte Yard at Birdwood, Nebraska, on July 11, 1984. Leading the train is EMD DDA40X “Centennial” No. 6912 paired up with a SD40-2.

Tight curves—short tunnel—long locomotive
Having just negotiated one of the sharpest curves on the Moffat Tunnel Subdivision at 12 degrees, a westbound Union Pacific (Bill Wimmer) p... (more)

A Union Pacific Passenger Special hosted by engineering department head Bill Wimmer lead by stately Heritage Fleet Centennial DDA40X #6936 enjoys Passenger Speed running through Grandview, Texas a... (more)

World’s largest diesel locomotive
In very much spring-like weather for Wyoming, with threatening clouds and a dusting of snow, an eastbound Union Pacific freight approaches Laramie in... (more)

The world's largest diesel locomotive, a Union Pacific's DDA40X, leads an eastbound intermodal train at Hermosa, Wyoming, in July 1984. Trailing No. 6913 are three new Norfolk Southern GE C39-8s. ... (more)

A UP DDA40X and an E9A (UP 949) sit in UP's Cheyenne Yard.

You can just feel the impatience of this scene: outbound crew is on board, waiting for the road foreman of engines to board (I don't know if that's him by the car, but I know the crew was waiting)... (more)

Like a big brother looking over the younger siblings, a tired and worn Big Jack awaits an inspection at the shop in the company of everyday power.

Not 100% sure on the train ID. From the very same bridge where I got my favorite shot of a jack, comes an eastbound TOFC in full whine sliding down the hill into Cheyenne. Sunlight is fitting on... (more)