Rocky Mountaineer, California Zephyr an two commuters at Denver Union Station.

Multiple trains leave the BNSF yard in Denver, Colorado, passing over the South Platte River as they run south.

A quartet of light motors sit in the Union Pacific's North Yard in Denver, Colorado.

A variety of light and heavy power sit in the North Yard in Denver, Colorado.

Photo by Jim Satterwhite. From my collection.

A golden sunrise catches the California Zephyr 6 train as it runs 12 hours late eastbound on the Brush Sub towards Commerce City, Colorado.

AMTK 148 (P42DC) leads the California Zephyr 6 train east on the Brush Sub, as it leaves Denver behind.

BNSF 9100 (SD70ACe) assists Amtrak's California Zephyr as it runs through the yard in downtown Denver, Colorado.

UP 737 (ex-Missouri Pacific GP38-2) waits in the North Yard in Denver, Colorado for the call to action to sort freight cars.

A variety of UP power sit in the North Yard in Denver, Colorado.

The Union Pacific's light motor of choice to work the North Yard in Denver, Colorado include GP38, GP39 and SD40N models. Here we see UP 1826 getting ready to pull a string of cars out for sortin... (more)

UP 737 (GP38-2) sits ready to move some oil cans in the North Yard in Denver, Colorado.

Former AT&SF Bluebonnet #2854 (GP39-2) teams up with former Burlington Northern #1448 (SD60M) as they work sorting cars in downtown Denver, Colorado.

UP 1019 (GP60) heads into the North Yard where the pair will sort cars in the north end of the yard in Denver, Colorado.

UP 1837 (SD40N) notches up as it pulls a cut of cars out for sorting in the North Yard in Denver, Colorado.