UPY 691 (GP15-1) sits in an industrial area in central Denver waiting for an assignment.

The North Yard in Denver offers a unique advantage point to photograph and video yard operations of the Union Pacific. The adjacent elevated viaduct has no fences to obstruct the view and the yar... (more)

UPY 691 (GP15-1) makes smoke as it repositions in the North Yard to pull another cut of freight cars for sorting.

It is a busy day in the UP's North Yard in Denver. Visible are four ex-Missouri Pacific engines (UP 825, UP 1823, UPY 691 and UPY 625). There is also an ex-Chicago & Northwestern (UPY 546) and a... (more)

UPY 691 (GP15-1) heads in after sorting a string of freight in the UP's North Yard in Denver.

A gaggle of Geeps moves a UP freight out of the BNSF's Denver Yard.

There is always a nice variety of power around the sand towers in the UP's North Yard in Denver.

UPY 691 (GP151) looks a bit weary among the other freshly painted UP power that can be found in the North and 36th Street Yards.

A ragged looking UPY 691 (GP15-1) comes out of the 36th Street Yard after spending the day sorting freight cars.

UPY 691 (GP15-1) is one of the last Geeps which has yet to be repainted, and you can see where the ex-Missouri Pacific blue is starting to wear through the UP yellow. Here it sits idle in the 36th... (more)

A pair of SP painted AC4400 units are seen resting at Denver's North Yard as other UP yard engines continue to sort cars on a clear summer morning. The BNSF S-OMATAC had just pulled into the BNSF... (more)

UPY 691 gets ready to take a string of freight cars from the North Yard.

UPY 691, a well-worn GP15-1 gets ready to pull a string of freight cars for sorting in the UP's North Yard in Denver. This engine started life in in 1982 for the Missouri Pacific Railroad, and if... (more)

BNSF 1923 (SD40-2) waits for the clearance to take a freight into the 36th Street Yard. Meanwhile, UPY 691 and two GATX units work the intermodal section of the yard.

UPY 691 (GP15-1) spends the afternoon sorting a colorful collection of containers in the 36th Street Yard.