BNSF 9716 (SD70MACe) pulls a freight in front of the historic Colorado & Southern depot in Longmont, Colorado.

UP 5802 (AC4400CW-CTE) leads a freight through the refineries at Commerce City, Colorado as it runs to Denver on the Greeley Sub.

BNSF 6056 (ES44AC) leads a Q train south on the Joint Line through Spruce, Colorado.

BNSF 9716 (SD70MACe) leads a freight down Atwood Street in Longmont, Colorado.

The temperature is -3 degrees as BNSF 5993 (ES44AC) leads a loaded coal train through Palmer Lake, Colorado on the Joint Line.

BNSF 7647 (ES44DC) leads a freight past the Three Oaks Ranch in Castle Rock, Colorado as it runs south on the Joint Line.

Coors Critter #998 will be 45 years old this year and still works hard running special hopper cars between the silo and the massive brewery in Golden, Colorado.

UP 1357 (ex Denver & Rio Grande Western GP40-2) sits next to the operations building in the Union Pacific's North Yard in Denver, Colorado.

UP's Western Pacific heritage engine #1983 (SD70ACe) stops at the North Yard in Denver for servicing.

With only seconds of sunlight left, UP 1997 (SD40N) leads the local through Greeley, Colorado on its way back to LaSalle.

UP 1957 (SD40N) and UP 1640 work sorting a cut of cars in the Union Pacific's North Yard in Denver, Colorado.

BNSF 1448 (SD60M) runs under the Denver RTD commuter rail track as it heads to Denver, Colorado with a string of oil cans from the refineries in Commerce City.

A fresh-looking BNSF 1448 (former Burlington Northern Cascade Green SD60M) gets ready to lash up to a cut of tank cars waiting at the refineries in Commerce City, Colorado.

Heavy snow covers the rocks above Tunnel #1 at Plainview, Colorado as the California Zephyr begins the journey through 28 tunnels between Denver and Winter Park.

20 inches of snow covers the Front Range as the California Zephyr runs through Coal Creek Canyon on its way into the Colorado Rocky Mountains.