UP 4922 (SD70M) leads a quartet of engines, including a BNSF motor, at Platteville, where it will pick up additional cars and then head further south on the Greeley Sub.

UP 4922 (SD70M) passes the silo at Peckham, Colorado as it heads south on the Greeley Sub.

UP 4922 (SD70M) leaves the yard in LaSalle, Colorado, running south on the Greeley Sub.

UP 4449 (SD70M) sits in downtown LaSalle, Colorado. It will soon get a new crew and will be assigned a train to take on the Greeley Sub.

UP 4449 (SD70M) has just dropped off a hopper train in the yard at LaSalle, Colorado.

UP 5725 (AC4400CW-CTE) waits on the siding in Tolland, Colorado as the Amtrak Winter Park Express Ski Train passes on the main track.

The snow is falling fast as UP 4404 (SD70M) waits for passengers to load up an officer's Special passenger train, which will run up the Moffat Tunnel Sub and through the Continental Divide.

The California Zephyr exits the Moffat Tunnel at Winter Park as it heads west on the Moffat Tunnel Sub.

The engineer for Amtrak's Winter Park Express Ski Train saddles up and gets ready to leave Winter Park, Colorado and enter the Moffat Tunnel on the journey back to Denver.

While heavy snow is falling, Amtrak's Winter Park Express Ski Train gets ready to leave the platform after dropping off a load of skiers at the resort.

The California Zephyr gets ready to cross Blue Mountain Road and will soon be running through the tunnel district of the Moffat Tunnel Sub.

The red glow from a Colorado sunrise shines off BNSF 5694 (AC4400CW) as it shoves a freight up the Moffat Tunnel Sub at Coal Creek Canyon.

BNSF 9322 (SD70ACe) joins fellow pumpkins and a Warbonnet in the BNSF engine servicing yard in Denver, Colorado.

Falling snow covers both the California Zephyr as it leaves the North Yard and the Union Pacific Officer Special passenger train that will soon follow the Zephyr up the Moffat Tunnel Sub.

The Union Pacific's North Yard in Denver, Colorado is the staging point for a number of Maintenance-of-Way equipment, including a few Plasser American Tamper machines.