The California Zephyr makes the steep climb up to tunnel number 1 as it heads into the Colorado Rocky Mountains. Notice one of the cars still carries the colorful Winter Park Ski Train wrap.

Under the watchful eyes of a group of cows, an oil can train doubles back on itself as it drops in grade through the Big 10 Curve near Rocky, Colorado.

Electro-Motive Division SD90MAC-H locomotives, along with EMD’s test car, head through Rocky, Colorado, for some testing at Plainview on February 2, 1998. Leading the way on the west end is EMD ... (more)

The golden light of dawn paints the scenery west of Rocky, Colorado, at 6:41 a.m. on the morning of July 26, 2014, as a Union Pacific inspection train arcs onto the mesa containing Big 10 Curve. T... (more)

A short Union Pacific inspection train approaches Big 10 Curve west of Rocky, Colorado, just after dawn at 6:41 a.m. on July 26, 2014. EMD SD70ACe No. 8734 leads power car UPP 207, sleeper “Port... (more)

Amtrak’s eastbound California Zephyr descends the grades of the Moffat Tunnel route rounding Big 10 Curve between Eisele and Rocky, Colorado, on the afternoon of May 4, 2018. Leading the train i... (more)

A westbound coal train led by Southern Pacific GE AC4400CW No. 314 is still sitting in the siding at Rocky, Colorado, after being run around by Ansco’s Rio Grande Ski Train a few minutes earlier... (more)

On the morning of August 4, 2001, Ansco’s Rio Grande Ski Train approaches Big 10 Curve between Rocky and Clay, Colorado. This summer edition of passenger train is being operated to Winter Park f... (more)

Amtrak’s California Zephyr climbs the front range of the Rocky Mountains between Rocky and Clay, Colorado, led by GE P40DC No. 821 on September 16, 2014.

The California Zephyr travels through the foothills west of Denver on its way to California.

About a half hour after departing the city of Denver seen looming above the plains in the background, Amtrak No. 5, the California Zephyr, sweeps around “Little 10 Curve” at Rocky, Colorado. R... (more)

As a Union Pacific coal train rolls eastbound through Rocky, Colorado, in the foreground, a following eastbound BNSF freight departs Plain and is about to enter Tunnel 1 in the background on Augus... (more)

A pair of EMD Demonstrator engines bring this loaded coal train Eastbound heading into Denver. The cars in the background are for the wind break on the Big Ten curve.

Looking up toward Big 10 Curve at Rocky, Colorado, sees a Burlington Northern Santa Fe train hauling coal eastbound descending the front range of the Rocky Mountains at Rocky, Colorado, on June 18... (more)

A Burlington Northern Santa Fe train hauling coal eastbound on Union Pacific’s Moffat Tunnel Subdivision descends the front range of the Rocky Mountains at Rocky, Colorado, on June 18, 2001. On ... (more)