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Tehachapi Loop - ASCE Plaque

Placed and commemorated in 1998 by History & Heritage Committee 

Los Angeles Section and Southern San Joaquin Branch 

American Society of Civil Engineers


The Tehachapi Loop is a 0.73-mile (1.17 km) long "spiral," or helix, on the Union Pacific Railroad line 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. Seeing a daily average of almost 40 trains, the line is one of the busiest single-track mainlines in the world.


With its frequent trains and spectacular scenery, the Loop is one of the prime railfan areas in the country. In 1998, the Loop was named a National Historic Civil Engineering Landmark and is now California Historical Landmark #508.

(from http://www.theloopnewspaper.com/story/2014/06/07/community/history-of-the-tehachapi-loop/615.html)


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In front of your is the world famous Tehachapi Loop which is about
halfway upgrade to Tehachapi Pass. This steep line averages 2.2% in
gradient in its 28 miles of length. This feat of civil engineering genius
was the crowning achievement of civil engineer William Hood of the
Southern Pacific Railway Company. It is one of the seven wonders of the
railroad world. 

The Tehachapi Pass Railroad Line was cut through solid and decomposed
granite by Up to 3000 Chinese laborers from Canton China. They used
picks, shovels, horse drawn carts and blasting powder. This line, which
climbs out of the San Joaquin Valley and through the Tehachapi
Mountains had 18 tunnels, 10 bridges and numerous water towers for the
old steam locomotives. It was completed in less than 2 years time under
the leadership of civil engineer J. B. Harris, Chief of Construction, a
remarkable feat.

This line was part of the last and final link of the first railroad line
connecting San Francisco to Los Angeles. It was a primary factor in the
early growth of the City of Los Angeles and the State of California.

This single track line, essentially unchanged, is still in constant use
today, 122 years after its completion. It passes an average of 36 freight
trains each day. This attests to the superior job of both engineering and
construction done by the two civil engineers and the Chinese laborers.
This plaque is dedicated to them

History & Heritage Committee
Los Angeles Section and Southern San Joaquin Branch
American Society of Civil Engineers

Submitted by

Bruce Deeter - ASCE member


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