Sunset falls along the Colorado Front Range as the California Zephyr #6 train drops into Coal Creek Canyon with a new Charger engine.

Operation Lifesaver Amtrak 6 is running east of the Great Divide with the OLS unit on lead.

Amtrak engine #160 in the 'Pepsi Can' 50th anniversary paint scheme leads the California Zephyr towards Tunnel #1 at Plainview, Colorado.

Amtrak engine #160 in the 'Pepsi Can' heritage scheme leads the California Zephyr towards Tunnel #1 at Plainview, Colorado.

The sumac is popping red as fall takes ahold of the Moffat Tunnel Sub. Here the California Zephyr runs towards Tunnel #1 at Coal Creek Canyon.

Amtrak engine #199 (P42DC) leaves the Crescent siding and gets on the main as it heads west on the Moffat Tunnel Sub.

The California Zephyr #6 train runs through the famed Big Ten Curve at Rocky, Colorado as it heads to Denver.

The Southwest Chief runs past a vintage AT&SF cantilever signal tower south of Trinidad, Colorado.

AMTK 160 (P42DC in the heritage 'Pepsi' paint scheme) runs through old Santa Fe cantilever signals just south of Trinidad, Colorado.

Amtrak engine 169 leads the California Zephyr 6 train past the golden aspen as it runs east on the Moffat Tunnel Sub through Tolland, Colorado.

BNSF 4250 (ES44C4) leads the California Zephyr over a bridge in Leyden, Colorado. This road will soon be widened to four lanes, which will necessitate the removal of the iconic Rio Grande Railroa... (more)

Amtrak engine #39 (P42DC) leads the California Zephyr through the Denver Yard as gets ready to back into Denver's Union Station.

A golden sunrise catches the Winter Park Express Ski Train as it kicks up some snow while running west on the Moffat Tunnel Sub.

The California Zephyr passes a herd of cows at Rocky, Colorado as the train heads towards Denver.

Amtrak engine #136 (P42DC) leads the California Zephyr through Tunnel #1 and will continue to drop in elevation as it heads to Denver on the Moffat Tunnel Sub.