The Rocky Mountaineer passenger train has 4 engines running in a push me - pull you configuration as it takes a load of passengers on a short trip to Eisele, Colorado and then back to Denver.
This view from the top of Blue Mountain gives a good view of the Big Ten Curve as the California Zephyr #6 train drops down the 2% grade towards Rocky, Colorado.
The lead engine on the California Zephyr looks like it's about to time travel as it runs through Rocky, Colorado on the Moffat Tunnel Sub towards Denver.