UPY 618 (GP15N) sorts a string of freight into the North Yard ladders in Denver, Colorado.

UPY 618 (GP15-1) works the Union Pacific's North Yard in Denver, Colorado.

UPY 618 (GP15-1) sorts a cut of hoppers into the various ladders in the Union Pacific's North Yard in Denver, Colorado.

UPY 618 (GP15-1) runs long hood forward and repositions a couple of tank cars in the yard in Commerce City, Colorado.

Shunting Suncor. Union Pacific Railroad GP15 no. Y618 is seen positioning tank cars at Suncor Energy USA in Commerce City, CO.

UPY 618 (GP15-1) sits in the North Yard in Denver, Colorado with a variety of other light and heavy power.

There is a mix of heavy and light power in the Union Pacific's North Yard in Denver, Colorado.

There is always a nice variety of light power in the Union Pacific's North Yard. Among the group on this day was UPY 618, an ex-Missouri Pacific GP15-1 that was built in September of 1979.

The Union Pacific still operates a number of former Missouri Pacific GP15-1's in the North Yard in Denver.

UPY 618 (GP15-1) was built in September of 1979 and can be found still working at the North Yard in Denver, Colorado.

UPY 618 (GP15N) joins other light power in the UP's North Yard in Denver, Colorado.

UPY 618 (GP15-1) works in the Union Pacific's North Yard in Denver, Colorado.

A surprise catch in the UP's North Yard in Denver was this bay window caboose, which is used for local runs as well as a 'snow bus', shuttling crews to trains in the mountains when heavy snow prev... (more)

UPY 618 (GP15-1) holds for a green signal to bring a small freight into a yard in Commerce City.

A variety of light power is active in the Union Pacific's North Yard in Denver, Colorado.