The California Zephyr runs through the curve at Plainview, Colorado on the Moffat Tunnel Sub.

Kansas City Southern 4765 (ES44AC) leads a Union Pacific train through Big Ten Curve as it drops down grade on the Moffat Tunnel Sub.

Denver & Rio Grande Western 491 (a Baldwin 2-8-2 built in 1902) runs freight around the grounds of the Colorado Railroad Museum in Golden, Colorado.

Rio Grande Southern #20 (4-6-0 locomotive built by the Schenectady Locomotive Works in 1899) gets a spin on the turntable as it gets ready to head into the barn for the day.

BNSF 3854 (ET44C4) leads the Z stack train towards Roggen, Colorado, while also carrying a Boeing 737 fuselage.

The snow is falling in Castle Rock, Colorado as BNSF 4252 (ES44C4) leads a long auto rack train south on the Joint Line.

BNSF 7485 (ES44AC) leads a freight through Tolland, Colorado as it heads to Denver on the Moffat Tunnel Sub

RTD 4033 passes an old water tower as it runs the elevated track along the Union Pacific's North Yard in Denver, Colorado.

BNSF 6081 runs through Hudson, Colorado on the Brush Sub under a bright golden sunrise.

UP 6643 (AC4400CW) leads an oil can train through Leyden, Colorado.

UP 6276 (ES44AC) leans into the curve at Tolland, Colorado as it runs down hill on the Moffat Tunnel Sub.

Rio Grande Southern Galloping Goose #7 makes laps at the Colorado Railroad Museum in Golden, Colorado.

The snow is falling fast as BNSF 4252 (ES44C4) takes a train through Spruce, Colorado.

BNSF 2857 (GP39-2) and mate pull a string of cars out of the Denver Yard and over the South Platte River for sorting.

BNSF 2949 (GP39-2) and another Geep take a single hopper to through Longmont, Colorado.