Amtrak’s westbound California Zephyr rumbles along the Colorado River, and is about to enter 463-foot Tunnel 42 just east of Radium, Colorado, on June 6, 2013.
Two Amtrak routes serve the Centennial State. The California Zephyr's route through Moffat Tunnel and along the Colorado River goes from one end of the state to the other. The Southwest Chief cuts across the southeast corner.