UP 1826 (SD40N) rousts the birds feeding on spilled grain in the Union Pacific's North Yard in Denver, Colorado.

UP 1826 (SD40N) takes a turn at sorting cars in the Union Pacific's North Yard in Denver, Colorado.

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

Sunrise in the Union Pacific's North Yard finds a stranger in a strange land, as a BNSF motor gets fuel and sand and the service island.

UP 1826 (SD40N) works a cut of cars in the North Yard in Denver, Colorado.

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

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

UP 1826 (SD40N) runs solo into the North Yard in Denver, Colorado.

The evening sun shines on the operations building in the Union Pacific's North Yard in Denver, Colorado.

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

Fresh snow covers the North Yard in Denver, Colorado as UP 1826 (SD40N) works on sorting a cut of cars into the various ladders in the yard.

UP 1826 (SD40N) sits in the North Yard in Denver, Colorado waiting for the call to sort freight cars.

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

UP 1826 (SD40N) sits on a siding in east Denver as a freight motors past and heads to the 36th Street Yard.

UP 1826 (SD40N) pulls up to the yard crew who will board as head to the north end of the yard.