The California Zephyr gets a helping hand from UP 4341 (SD70M) as it runs by the Cold War Horse sculpture and heads into the Moffat Tunnel district and the Colorado Rocky Mountains.
The subfreezing temps caused issues with one of the P42's so the Union Pacific added an engine up front to take the Zephyr through the Colorado Rockies.
UP SD70M 4341, 4508 & GE ES44AC 7461 enter Echo Canyon area with an eastbound military train.