UP 618 (GP15N) moves into the Union Pacific's North Yard in Denver to sort freight cars.

The California Zephyr runs through 'The Cut' as it heads towards Rocky, Colorado on the Moffat Tunnel Sub.

The California Zephyr leaves Denver's Union Station and runs under the Park Avenue Viaduct which is adjacent to the BNSF engine servicing facility.

The California Zephyr runs towards Keenesburg, Colorado on the Brush Sub as a bright sunrise creates a golden glow.

A pair of Geeps wait for orders to head to the Denver Yard to sort freight cars.

BNSF 4252 (ES44C4) runs through Monument, Colorado as a late spring storm dumps snow along the Front Range.

A late spring snowstorm has dumped over a foot of snow in the Colorado Rockies, giving passengers on the California Zephyr one last view of a winter wonderland.

Amtrak heritage engine 184 (P42DC) sits next to the Winter Park Express Ski Train at Denver's Union Station.

The California Zephyr #5 runs through the BNSF yard in Denver before backing into Union Station.

The California Zephyr runs through Fort Morgan, Colorado at sunrise.

UP 7956 (AC45CCTE) leads a Herzog ballast train into the setting sun.

UP 6276 (ES44AC) is framed by the trees at Rocky, Colorado.

UP 8018 (ES44AC) leads a freight out of the fog and through the signals as it enters the large yard in Cheyenne, Wyoming.

UP 6276 (ES44AC) leads an oil can train through Coal Creek Canyon on the Moffat Tunnel Sub.

UP 3974 (SD70M) runs solo back to Denver, passing between the Commerce City refineries on the Greeley Sub.