A trio of SD40's are at the ready in the Union Pacific's North Yard in Denver, Colorado.

UP 1640 (SD40N) and UP 1344 (GP40-2) wait in the North Yard in Denver, Colorado for orders.

UP 1640 (SD40N) moves through the BNSF's Denver Yard after dropping off a cut of cars.

UP 1640 (SD40N) works a cut of cars in the Union Pacific's North Yard in Denver, Colorado.

UP 1640 SD40N sorts oil cans in the North Yard as a pair of BNSF motors arrange a stack track in the adjacent intermodal facility.

UP 1640 is one of many SD40N units that can be currently found working the North Yard in Denver.

The massive snow storm not only shut down the BNSF for two days but also stopped all Union Pacific Traffic (as well as all RTD light rail and commuter trains). Tracks remain snow covered with sno... (more)

UP 1640 (SD40-2 rebuilt to a SD40N) waits with other light power for assignment in the Union Pacific's North Yard in Denver, Colorado.

A variety of engines wait for servicing in the UP's North Yard while UP 1640 (SD40N) continues to sort freight cars.

The remote control operator of UP 1640 (SD40N) sends a long freight south of the North Yard so that the individual cars can then be sorted.

UP 1640 (SD40N) and mate work the North Yard in Denver sorting freight cars while UP 3922 (SD70M) gets ready to lead two other power units and a long freight out of the yard.

UP 1640 works a frozen 36th Street Yard in Denver.

UP SD40N #1640 and SD70ACe #8310 bring their train east through De Beque Canyon on its way to switch Parachute

You can always find a variety of light duty engines in the UP's 36th Street Yard. Denver's RTD also constructed a commuter rail station adjacent to the yard, which will provide interesting opport... (more)

With evening temperatures hovering around 10 degrees, UP 1640 (SD40-2 rebuilt as a SD40N) brings a crew into the 36th Street Yard.