One of the greatest engineering feats of its day, the Loop was built by the Southern Pacific RR to ease the grade over the Tehachapi Pass. Construction began in 1874, and the line opened in 1876.
Rising at a steady 2% grade, the track gains 77 feet in elevation in the Loop. A train more than 4,000 feet long passes over itself as it goes around the loop.
© Allen Hirsch Photography