UP 1997 (SD40N) moves through the North Yard in Denver, Colorado.

UP 1997 (SD40N) reflects off a puddle in the North Yard in Denver, Colorado.

With only seconds of sunlight left, UP 1997 (SD40N) leads the local through Greeley, Colorado on its way back to LaSalle.

UP 1997 (SD40N) and other light power wait in the Union Pacific's North Yard for assignments as heavies fuel and sand up at the servicing islands.

The operations building in the Union Pacific's North Yard in Denver, Colorado has a commanding view of the massive yard.

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

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

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

There is usually a lot to see in the Union Pacific's North Yard in Denver, Colorado. Light power will be shuffling cars in the yard and heavy power can usually be spotted coming and going at the ... (more)

UP 1997 is one of many SD40N units currently found working the large North Yard in Denver, Colorado.

The bright sun and the snow really makes the Amour Yellow pop on the motors in the Union Pacific's North Yard.

A group of light power sits in the Union Pacific's North Yard waiting for assignments.

UP 1997 (an SD40-2 rebuilt as a SD40N) waits for orders in the Union Pacific's North Yard in Denver, Colorado.

A pair of light power get ready to sort cars in the UP's North Yard. UP 1997 was built in 1970 as a GP38AC for Illinois Central, then worked for the Missouri Kansas Texas Railroad, then US Sugar ... (more)

Light power is busy in the Union Pacific's North Yard in Denver, Colorado. UP 1997 has had an interesting career, having been built in 1970 as a GP38AC for Illinois Central, then worked for the M... (more)