UP 1817 (SD40N) sits in the Union Pacific's North Yard in Denver, Colorado.

UP 1826 (SD40N) pulls up to the yard crew who will board as head to the north end of the yard.

I think Alfred Hitchcock would have liked this photo. UP 1826 (SD40N) works the Union Pacific's North Yard in Denver, Colorado as hundreds of birds circle, waiting for the chance to land on the tr... (more)

A Union Pacific oil can train is seen from inside a rock formation at Crescent, Colorado.

It's the blue hour in Denver, Colorado as UP 6999 (AC4400CW) leads an oil can train towards the 36th Street Yard.

The snow is so deep that UP 8051 (ES44AC) pushes a wall of snow ahead of the train as it heads to Denver, Colorado on the Moffat Tunnel Sub.

UP 8051 (ES44AC) has emerged from the Moffat Tunnel into a heavy snow storm and will slowly lead an oil can train towards Denver, Colorado.

A solid set of Union Pacific power takes NS train 226 eastbound through Tallapoosa, GA on their way to Atlanta, GA. Train 226 originated in Shreveport, LA from the Union Pacific with a UP the symb... (more)

A visiting BNSF motors sits among the Union Pacific motors in the UP's 36th Street Yard in Denver, Colorado.

UP 8612, 7273, & 5271 westbound with an intermodal train.

UP 7399 & 6758 lead a westbound manifest.

UP 8742 & 6713 with eastbound stacks.

UP 8228 leads an eastbound stack train.

UP 5953 holds the siding with coal for San Antonio while the engineer (or conductor) comes out to give a visual once-over of an eastbound, near sunset.

A pair of GE C44ACMs bring up the rear of a westbound intermodal passing through Modesto.