Historic Sites and Points of Interest in Nevada County

Great Summit Tunnel of the Sierra Nevada Sugar Bowl Road Overpass and Tunnel #6
Great Summit Tunnel of the Sierra Nevada 2 September 2014
(Click Photos to Zoom)
Great Summit Tunnel
AKA Central Pacific Railroad Tunnel #6
Sugar Bowl Road at Railroad Overpass
Donner Summit
Completed 1867

Central Pacific Railroad Tunnel #6 remains virtually the same today as it did when Lewis Clement saw the first CPRR train roll through it on November 30, 1867, after two years of continuous labor.

The tunnel was taken out of service in 1999 and the tracks were removed after 130 years of continuous use.

Tunnel #6 is the longest tunnel of the historic CPRR tunnels in the Sierra Nevada. Its length is 1,659 feet and its greatest depth below the surface is 124 feet. The tunnel was cut through granite crossed by seams in all directions.

To expedite the work a shaft was sunk about the middle of the tunnel. For the first 30 feet, it was sunk at the rate of a foot a day, after which its progress slackened, from delay in hoisting the material with a common hand derrick.

Source: Adapted from Central Pacific Railroad Photographic History Museum

You can view an historic marker about 1,500 feet from here where the Pacific Crest Trail crosses Donner Pass Road. The marker is positioned above the shaft.

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