UP 7689 (ES44AC) runs through Greenland, Colorado at sunset.

UP 1826 SD40N moves past a trio of BNSF motors sitting in the Union Pacific North Yard.

UPY 453 (which is a former Missouri Pacific SD40-2 converted to a slug by removing the prime motor) is spotted in the North Yard in Denver, Colorado.

BNSF 1590 (SD40-2) runs long hood forward and drags some stack cars to the yard in Denver, Colorado.

Snow has provided a white backdrop for BNSF 2530 (GP39-3) as it waits for a crew in Longmont, Colorado.

BNSF 6152 (ES44AC) hits the signals at Nixon, Colorado as it heads north on the Joint Line.

UP 4363 (SD70M) leads a freight towards Fort Lupton, Colorado on the Greeley Sub.

UP 5640 (ES44AC) joins a mix of light and heavy power in the Union Pacific's North Yard in Denver, Colorado.

UP 8640 (SD70ACe) gets repositioned in the Union Pacific's North Yard in Denver, Colorado.

BNSF 6258 (ES44AC) runs an empty coal towards Keenesburg, Colorado and into a golden sunrise.

BNSF 3127 (GP50) waits in the engine servicing yard for its turn in the Denver Yard. Also visible is the special cars for fighting fires along the tracks. These were not needed this year, thankf... (more)

The California Zephyr rounds the corner at Blue Mountain and will soon pass through the first of 29 tunnels on the Moffat Tunnel Sub.

The California Zephyr runs through the signals at Keenesburg, Colorado as it heads to Denver under a golden sunrise.

The California Zephyr glints the gold sunrise as it runs through Keenesburg, Colorado on the Brush Sub.

Snow from the day before covers BNSF 2530 (GP39-3) and the historic Longmont Depot in Colorado.