UP 688 (GP38-2) runs long hood forward in a Siamese configuration as it works shuffling cars in the North Yard in Denver, Colorado.

UP 688 (GP38-2) repositions in the North Yard to assemble a train.

UP 688 (GP38-2) runs into the Union Pacific's North Yard in Denver, Colorado to sort freight cars.

UP 688 (GP38-2) works a yard in Commerce City, Colorado, waiting for the signal to grab a cut of gondolas from a nearby scrap metal business.

Light power waits for orders in the Union Pacific's North Yard in Denver, Colorado.

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.