UP 688 (GP38N) moves into the North Yard in Denver, Colorado to sort rolling stock.

UP 688 (GP38N) runs in the Union Pacific's North Yard in Denver, Colorado.

A wide shot at the Union Pacific's North Yard in Denver catches two trains that have just entered the yard, while UP 688 (GP 38-2) begins to sort a cut from a train that arrived the day before.

UP 688 (GP38-2) pulls a cut of cars out of the Union Pacific's North Yard, which will then get sorted onto various tracks.

UP 688 (GP38-2) strains to pull a cut of cars out of the North Yard for sorting.

Light power shuffles in the Union Pacific's North Yard in Denver, Colorado.

UP 688 is one of many ex-Missouri Pacific GP38-2 units now in Union Pacific service. Here we see a remote control yard operator shove a cut of gondolas into the Denver North Yard.

UP 688 (Ex Missouri Pacific GP38-2) is among the units sitting in the Union Pacific's North Yard in Denver, Colorado.

A trio of UP light power move into the North Yard to tackle moving some cars.

Light power dominates the Union Pacific North Yard in Denver, Colorado.

"UP Local at Suncor Gate 116" A Union Pacific local shoves loads into Suncor's Gate 116. The Suncor's Denver location is a huge refinery that is served by both BNSF (Brush Subdiv... (more)

It seems the majority of the rolling stock passing through the North Yard these days are center-beam cars full of lumber to feed the rapid development along the Front Range of Colorado.

UP 688 (GP38-2) muscles a long cut of cars out of the North Yard for sorting.

UP 688 (GP38-2) and UPY 586 (GP15-1) have somehow avoided the refresh program. Here they team up to move cars in the UP's North Yard in Denver.

UP 688 strains to pull a cut of cars out of the North Yard for sorting.