The California Zephyr makes the climb to Tunnel #1, along a stretch of track that has 3.4% grade, the steepest grade on the Moffat Tunnel District.

A passenger standing in the back window gives a friendly wave as Amtrak heritage engine 184 (P42DC) leads the California Zephyr through Plainview, Colorado on the Moffat Tunnel Sub.

UP 5131 (SD70M) leads the Rocky Mountaineer passenger train up the Moffat Tunnel Sub towards Tunnel 1 at Plainview, Colorado.

The California Zephyr is emerging from Tunnel 1 at Plainview, Colorado.

Amtrak heritage engine 184 (P42DC) leads the California Zephyr out of Tunnel 1 at Plainview, Colorado. A friendly wave and a horn toot from Engineer Gary was most appreciated!

Amtrak engine 28 leads the California Zephyr through Plainview, Colorado and within the hour will be stopping in Denver's Union Station.

The rolling hills of Coal Creek Canyon and Plainview, Colorado provide a scenic backdrop to heritage engine 184 as it runs the California Zephyr on the Moffat Tunnel Sub.

Heavy snow has coated the Boulder Flatirons rock formation as the California Zephyr makes the trek into the Moffat Tunnel Sub.

Amtrak engine 138 (P42DC) leads the California Zephyr through the sweeping curve at Plainview, Colorado.

From atop tunnel 1 on UP’s Moffat Tunnel Subdivision, we see the Rocky Mountaineer snaking around the bend led by a pair of UP SD70Ms as the begin their journey west through the Rockies.

Amtrak heritage engine 184 (P42DC) rounds the corner leading up to Tunnel #1 at Plainview, Colorado.

Led by a matched pair of GE P42DCs, Amtrak’s westbound California Zephyr begins its journey through the Rockies on UP’s Moffat Tunnel Subdivision, framed from atop tunnel 1 near Plainview, CO.... (more)

Overlooking Coal Creek Canyon near Plainview, CO, Amtrak’s California Zephyr is seen beginning it’s route through the Rockies on UP’s Moffat Tunnel Subdivision.

The California Zephyr 5 train typically leaves Denver's Union Station around 8:15am, and this stretch of Moffat Tunnel Sub heads almost due east, providing an opportunity for a well-lit morning sh... (more)

A triple headed California Zephyr runs through the trees at Plainview, Colorado.