Amtrak #5 'The California Zephyr' clings to the side of Little Gore Canyon between tunnels 39 and 40 near Azure, CO.

An eastbound Union Pacific oil train passes through Azure, Colorado, as it enters rugged Gore Canyon on Union Pacific’s scenic Moffat Tunnel Subdivision on June 24, 2024.

The sun has just risen above the mountains to illuminate Union Pacific's MGJNY working through 'Azure' before dipping into Gore Canyon.

An empty UP oil train catches a quick sliver of sun as it navigates through Little Gore Canyon near Azure, CO.

Amtrak’s California Zephyr threads 100-foot Tunnel 38 as it negotiates Gore Canyon approaching Azure, Colorado, on September 20, 2023. This scenic former Rio Grande main line is now Union Pacifi... (more)

Amtrak’s westbound California Zephyr follows the Colorado River through rugged Gore Canyon as it approaches Azure, Colorado, on September 20, 2023. The train is about to enter 100-foot Tunnel 38... (more)

A westbound Union Pacific coal empty approaches Azure, Colorado, as it exits Gore Canyon and snakes through Tunnel 38 on June 19, 2023. Powering the train is dirty GE AC4400CW-CTE No. 5682 and new... (more)

On June 19, 2023, Amtrak train 5, the westbound California Zephyr, threads through 100-foot Tunnel 38 just east of Azure, Colorado, as it follows the Colorado River through Gore Canyon.

An eastbound “Rockies to the Red Rocks” Rocky Mountaineer luxury passenger train passes through Gore Canyon between Azure and Gore, Colorado, on Union Pacific’s Moffat Tunnel Subdivision dur... (more)

The sheer depth of the rock walls lining Gore Canyon dwarf Amtrak’s California Zephyr as it approaches Azure, Colorado, on September 15, 2021.

Looking a bit like an N scale model, Amtrak’s westbound California Zephyr edges the rocky cliffs through Gore Canyon at Azure, Colorado, on September 15, 2021.

A westbound California Zephyr emerges from a tunnel in Gore Canyon as it hugs the banks of the Colorado River.

A pair of Union Pacific EMD SD70Ms, wrapped and patched for Rocky Mountaineer Railtours, powers the westbound luxury passenger train westbound along the Colorado River through Gore Canyon east of ... (more)

A Rio Grande coal train snakes through the multiple curves leaving the east switch at Azure, Colorado, entering Gore Canyon along the Colorado River. A trio of EMD SD40T-2 Tunnel Motors lead the e... (more)

A Union Pacific coal load, led by Kansas City Southern GE ES44AC No. 4891, departs Azure, Colorado, during some of the last light of day on November 15, 2021. The eastbound train is following the... (more)