Amtrak No. 5, the California Zephyr, climbs the front range of the Rocky Mountains just west of Plainview, Colorado, on February 28, 2011. Passing through the Flatirons, the silvery train is exiting Tunnel 2, threading a rock cut and about to enter Tunnel 3. Some rear cars of No. 5 are passing over the fill that washed away in the Colorado flooding of September 2013.