Tehachapi Loop

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Aerial overview of the Tehachapi Loop in 2022
BNSF train on Tehachapi Loop in 2011, with mixed trailer-on-flatcar and double-stack container manifest
An eastbound Santa Fe train passes over itself on the loop in April 1987
A panoramic view of the Tehachapi Loop looking north-west
Pictorial cancellation from the Keene Post Office celebrating the Loop's 129th anniversary
National Historic Civil Engineering Landmark identifier

The Tehachapi Loop is a 3,779 feet (0.72 mi; 1.15 km) long spiral,[1] 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 a 1,210-foot (370 m) diameter circle.[1][2] Any train that is at least 3,800 feet (1,162 m) (approx. 56 60’(67'11") box cars) long 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;[1] passenger services such as Amtrak's San Joaquin are banned from using the loop, while the Coast Starlight can only use it as a detour.[3] Its frequent trains and scenic setting make the Tehachapi Loop popular with railfans.[3][4] In 1998, it was named a National Historic Civil Engineering Landmark; it is also designated as California Historical Landmark #508.[5]


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 the line opened in 1876.[1][6] Contributors to the project's construction include Arthur De Wint Foote and the project's chief engineer, William Hood.[7]

The siding on the loop is known as Walong after Southern Pacific District Roadmaster W. A. Long.[8][9]

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.[3] The Tehachapi line necessitated 18 tunnels, 10 bridges, and numerous water towers to replenish steam locomotives.[1] 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 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).[10] In 1882, the line was extended through Southern California and the Mojave Desert with 8,000 Chinese men working under Strobridge and another man.[11]

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 a train derailment in San Bernardino, California.[6]

The Tehachapi Depot Museum is located in the nearby town of Tehachapi.[12]


The Loop became the property of the Union Pacific Railroad in 1996, when the Union Pacific and Southern Pacific systems merged.[13] Trains of the BNSF Railway also use the loop under trackage rights.[3]

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.[3] As a result, Amtrak's San Joaquin train is unable to directly serve Los Angeles.[3] Amtrak operates Thruway Motorcoach 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.[3][14][15]

California Historical Landmark[edit]

The California Historical Landmark plaque reads:

NO. 508 TEHACHAPI LOOP - From this spot may be seen a portion of the world-renowned Loop completed in 1876 under the direction of William Hood, Southern Pacific railroad engineer. In gaining elevation around the central hill of the Loop, a 4,000-foot train will cross 77 feet above its rear cars in the tunnel below.[16]

The markers at the overlook were rearranged when a viewing platform was constructed at the scenic overlook on Woodford-Tehachapi Road in the summer of 2021. The cement platform was built so that railroad enthusiasts can view trains on the loop while keeping a safe distance from the winding, two-lane roadway.[17]

See also[edit]


  1. ^ a b c d e "Tehachapi Pass Railroad Line". asce.org. American Society of Civil Engineers. Retrieved 22 October 2020.
  2. ^ Ande, Howard (2010). "Tehachapi in the 21st Century". NRHS Bulletin. National Railway Historical Society. 75 (Spring 2010): 4–21.
  3. ^ a b c d e f g McFadden, Christopher (2017-02-11). "Going Round the Bend With the Tehachapi Loop". interestingengineering.com. Retrieved 2021-05-25.{{cite web}}: CS1 maint: url-status (link)
  4. ^ Lustig, David (July 2022). "Hotspot: California's Tehachapi Mountains". Trains. 82 (7): 46–47.
  5. ^ "Tehachapi Loop". Office of Historic Preservation, California State Parks. Retrieved October 7, 2012.
  6. ^ a b "Tehachapi Loop history". Tehachapi_online. Archived from the original on November 18, 2011. Retrieved December 1, 2011.
  7. ^ Rickard, Thomas Arthur (1922). Interviews with Mining Engineers. San Francisco: Mining and Scientific Press. p. 172. OCLC 2664362. Arthur De Wint Foote.
  8. ^ Jenkins, Jim C. & Jenkins, Ruby Johnson (1995). Exploring the Southern Sierra, West Side. Wilderness Press. p. 23. ISBN 0-89997-181-4.
  9. ^ Durham, David L. (1998). California's Geographic Names. Quill Driver Books. p. 1124. ISBN 1-884995-14-4.
  10. ^ Chang, Gordon H.; Fishkin, Shelley Fisher (2019-04-30). The Chinese and the Iron Road: Building the Transcontinental Railroad. Stanford University Press. ISBN 978-1-5036-0925-9.
  11. ^ Graybill, Andrew (2019-05-10). "The Forgotten History of the Chinese Who Helped Build America's Railroads". The New York Times. ISSN 0362-4331. Retrieved 2021-05-25.
  12. ^ "The Tehachapi Depot Railroad Museum is reopening". The Loop Newspaper. October 24, 2020. Retrieved 2021-05-25.{{cite web}}: CS1 maint: url-status (link)
  13. ^ "Tehachapi Loop". digital-desert.com. Walter Feller. Retrieved 13 June 2022.
  14. ^ Shepard, Stacey. "All aboard! Train makes rare trip over Tehachapi Loop". The Bakersfield Californian. Retrieved 13 June 2022.
  15. ^ "Passenger trains will be diverted over Tehachapi Loop". Tehachapi News. 1 March 2013.
  16. ^ "Landmark chl-508 Tehachapi Loop". californiahistoricallandmarks.com. August 26, 1953. Retrieved 2022-06-13.{{cite web}}: CS1 maint: url-status (link)
  17. ^ Smirnoff, Nick (July 27, 2021). "New Tehachapi Loop Overlook Celebrated". Tehachapi News. Retrieved October 21, 2021.

External links[edit]

Coordinates: 35°12′03″N 118°32′13″W / 35.20083°N 118.53694°W / 35.20083; -118.53694