A spiral (sometimes called a spiral loop or just loop ) is a technique employed by railways to ascend steep hills.
12-800: The Tehachapi Loop is a 3,779-foot-long (0.72 mi; 1.15 km) spiral , or helix , on the Union Pacific Railroad Mojave Subdivision through Tehachapi Pass , of the Tehachapi Mountains in Kern County , south-central California . The line connects Bakersfield and the San Joaquin Valley to Mojave in the Mojave Desert . Rising at a steady two-percent grade, the track gains 77 feet (23 m) in elevation and makes
24-417: 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 San Joaquins are banned from
36-467: A train derailment in San Bernardino, California . 35°12′03″N 118°32′13″W / 35.20083°N 118.53694°W / 35.20083; -118.53694 Spiral (railway) A railway spiral rises on a steady curve until it has completed a loop, passing over itself as it gains height, allowing the railway to gain vertical elevation in a relatively short horizontal distance. It
48-403: Is an alternative to a zig-zag , and avoids the need for the trains to stop and reverse direction while ascending. If the train is longer than the length of each loop it may be possible to view it looping above itself. The term "loop" is also often used for a railway that curves sharply and goes back on itself: if the railway crosses itself, then it forms a spiral or helix ; otherwise, it forms
60-581: The 1,000 mm ( 3 ft 3 + 3 ⁄ 8 in ) gauge railway line from Kenya to Uganda . This railway has been superseded by the Mombasa–Nairobi Standard Gauge Railway , which has removed the need for spirals by constructing tunnels and bridges. San Bernardino train disaster Too Many Requests If you report this error to the Wikimedia System Administrators, please include
72-521: The BNSF Railway also use the loop under trackage rights . Although Southern Pacific ran passenger trains on the Loop for years, it banned passenger service there soon after handing its trains to Amtrak in 1971. Union Pacific has maintained the ban since taking over Southern Pacific. As a result, Amtrak's San Joaquin train is unable to directly serve Los Angeles until a bypass is constructed or
84-685: The United States federal government or the California State Legislature compel the railroad to allow passenger service to resume. Amtrak operates Amtrak Thruway buses for passengers wanting to travel between the Central Valley and Los Angeles. An exception is made for the Coast Starlight , which uses the line as a detour if its normal route is closed. A concrete viewing platform was constructed at
96-627: The helix -shaped 0.72-mile (1.16 km) loop with grades averaging about 2.2 percent and an elevation gain of 77 feet (23 m). In 1882, the line was extended through Southern California and the Mojave Desert with 8,000 Chinese men working under Strobridge and another man. The Loop became the property of the Union Pacific Railroad in 1996, when the Union Pacific and Southern Pacific systems merged. Trains of
108-748: The line opened in 1876. Contributors to the project's construction include Arthur De Wint Foote and the project's chief engineer, William Hood. The siding on the loop is known as Walong after Southern Pacific District Roadmaster W. A. Long. The project was constructed under the leadership of Southern Pacific's civil engineers, James R. Strobridge and William Hood, using a predominantly Chinese labor force. The Tehachapi line necessitated 18 tunnels, 10 bridges, and numerous water towers to replenish steam locomotives. Between 1875 and 1876, about 3,000 Chinese workers equipped with little more than hand tools, picks, shovels, horse-drawn carts and blasting powder cut through solid and decomposed granite to create
120-518: 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. One of the engineering feats of its day, the Loop was built by Southern Pacific Railroad to ease the grade over Tehachapi Pass. Construction began in 1874, and
132-623: The much more common horseshoe curve or bend . Replica of the Brusio Spiral Viaduct at 10°28′44″N 84°49′25″W / 10.47900°N 84.82374°W / 10.47900; -84.82374 on the Tren Turistico Arenal , 10 km east of Nuevo Arenal, Guanacaste. The Darjeeling Himalayan Railway originally had five or six spirals but only five in operation at any one time. The line also has six reverses or zig-zags . There are three spirals on
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#1732780203006144-488: The scenic overlook on Woodford-Tehachapi Road in the summer of 2021, allowing railroad enthusiasts to watch trains on the loop at a safe distance from the winding, two-lane roadway. The Tehachapi Depot Museum is located in the nearby town of Tehachapi . The California Historical Landmark plaque reads: A large white cross, "The Cross at the Loop", stands atop the hill in the center of the loop in memory of two Southern Pacific Railroad employees killed on May 12, 1989, in
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