Tehachapi Loop

The Tehachapi Loop is an iconic spiral loop, 1.17 km long, that passes over itself as it gains height on the railroad main line through Tehachapi Pass, in south central California. The loop was constructed in the latter half of the 19th century as part of Southern Pacific's main line through southern California, which had to cross the Tehachapi Mountain range. More than 3,000 Chinese immigrant laborers toiled for two years cutting through the solid granite with blasting powder, and then clearing the debris using picks, shovels, and horse drawn carts, to lay the Tehachapi Pass Railroad Line. The line, which climbs out of the San Joaquin Valley and through the Tehachapi Mountains to Mojave in the Antelope Valley, was part of the last and final link of the first railroad line connecting San Francisco to Los Angeles.

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Photo credit: Roger Snyder

The aim of the Tehachapi Loop was to gain elevation at a manageable gradient, and this has worked so well for nearly 140 years that it continues to be used even today. In fact, it one of the busiest single-track mainlines in the world with an average of almost 40 trains passing through the Loop each day. The frequent trains and the spectacular scenery makes the Loop a prime draw for trainspotters in the country. The engineering feat has earned the Loop the dual status of being a National Historic Civil Engineering Landmark as well as a California Historical Landmark.

Related Reading: Brusio Spiral Viaduct in Switzerland

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