Tehachapi Loop

The Tehachapi Loop is a 3,779-foot-long (0.72 mi; 1.15 km) rail spiral (or helix) on the Union Pacific Railroad's Mojave Subdivision through the Tehachapi Pass in the Tehachapi Mountains in Kern County, south-central California. The line connects Bakersfield and the San Joaquin Valley to the town of Mojave in the Mojave Desert. Rising at a steady two-percent grade, the track gains 77 feet (23 m) in elevation and makes a 1,210-foot-diameter (370 m) circle. Any train that is more than 3,800 feet (1,200 m) long—about 56 boxcars—passes over itself going around the loop. At the bottom of the loop, the track passes through Tunnel 9, the ninth tunnel built as the railroad was extended from Bakersfield. The line averages about 36 freight trains each day. Passenger trains such as Amtrak's Gold Runner are banned from the loop, although the Coast Starlight can use it as a detour. Its frequent trains and scenic setting make the Tehachapi Loop popular with railfans. In 1998, it was named a National Historic Civil Engineering Landmark. It is also designated as California Historical Landmark #508.