UP 7104 (AC4400CW) leads the Grand Junction to Denver train through Big Ten Curve as it drops in altitude and heads towards Denver, Colorado.

The California Zephyr exits Tunnel #1 at Plainview, Colorado. There will be 28 more tunnels before the train crosses under the Continental Divide.

Amtrak 5 with an Phase VII P42DC leading, heads westbound on the UP Moffat Subdivision in a May snowstorm in the Rocky Mountains.

RMRX 8020 leads the "Rockies To Red Rocks" train west through Colorado's Western Slope while making its way out of a canyon.

The Winter Park Express runs through Crescent, Colorado after nearly 4 feet of snow fell in the valley the night before.

Amtrak engine #187 (P42DC) leads the California Zephyr #6 train through Pinecliffe, Colorado as it heads to Denver on the Moffat Tunnel Sub.

UP 4533 (SD70M) leads an officer passenger train around the windbreak at Big Ten Curve as it heads into the Colorado Rocky Mountains.

RMRX 8020 leads the Rockies To Red Rocks train through Byers Canyon.

Freezing fog and light snow shrouds Tunnel #4 at Plainview, Colorado as UP 8530 (SD70ACe) leads the Grand Junction to Denver freight down the Moffat Tunnel Sub.

UP 4533 (SD70M) leads an officer special passenger train under Highway 93 and towards Rocky, Colorado.

BNSF 5866 (ES44AC) exist Tunnel #29 at Pinecliffe, Colorado and will continue down the mountain towards Denver on the Moffat Tunnel Sub.

A distant horn signaled the pending arriving of BNSF 5866 (ES44AC) at Pinecliffe, Colorado, and within seconds the freight train rounded the corner and headed into Tunnel #29.

A keyhole in the clouds allows a spotlight of sun to shine on a Union Pacific Officer Special as it runs through Coal Creek Canyon, Colorado.

UP 8530 (SD70ACe) leads a freight down the hill from Tunnel #1 and into Coal Creek Canyon, Colorado as it heads to Denver on the Moffat Tunnel Sub.

Wrap Around Photo. Union Pacific Railroad 2528 (ES44AC-H/C45AH) leads a robust six-pack of power through Coal Creek Canyon approaching Blue Mountain Drive in Aravada, Colorado on July 28, 2... (more)