UP 1817 (SD40N) gets repositioned in the North Yard in Denver, Colorado.

UP 1957 (SD40N) moves south in the North Yard as the Amtrak's Winter Park Express Ski Train heads north.

Snow clouds are moving in as UP 1957 (SD40N) works the North Yard in the evening sun.

UP 1826 (SD40N) moves with two other light power units through the North Yard in Denver, Colorado.

UP 1997 (SD40N) holds station in the Union Pacific's North Yard in Denver, Colorado.

UP 1845 (SD40N) makes a run into the large Union Pacific yard at Cheyenne, Wyoming.

A variety of Union Pacific motors spotted in the North Yard in Denver, Colorado.

UP 1957 (SD40N) works the North Yard in Denver, Colorado.

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

UP 1826 (SD40N) works shuffling cars in the North Yard in Denver, Colorado.

UP 1865 (SD40N) waits in the North Yard for its turn to shuffle freight cars.

UP 1826 (SD40N) has yard sorting duty as it heads into the North Yard for another cut of cars.

The fresh snow really makes the Armour Yellow of UP 1997 and the other motors in the North Yard pop.

UP 1826 (SD40N) works the Union Pacific's North Yard in Denver, Colorado.

UP 1826 (SD40N) works the North Yard in Denver, Colorado as other engines are getting service.