The Hetch Hetchy Railroad, built by San Francisco to provide high-capacity and all-weather form of transportation to move heavy machinery, bulk materials and supplies, and workers into the mountains to the O’Shaughnessy Dam site. It was a 68-mile-long, standard gauge railway, from Hetch Hetchy Junction, some 26 miles east of Oakdale, to the rim of the Hetch Hetchy Valley.
Hetch Hetchy Railroad operated as a common carrier from July 1918 to February 1925, subject to rules of the California Railroad Commission. It abided by railroading practices, publishing time tables and tariffs. But it was a different sort of railroad. Mayor Rolph was president of the line, Chief O’Shaughnessy was vice president and general manager. There was considerable informality in its operation – the management consisted of civil engineers, not locomotive engineers.
Most of the mountain construction work on the was completed by the mid-1920s, but the railroad was kept in use for another two decades, mostly for winter supply and maintenance while motor roads were snowbound. The railroad was again used for construction in the 1930s to haul materials and workers to raise O’Shaughnessy Dam to its current height of 430 feet.
Built for some $3 million, Hetch Hetchy Railroad saved at least ten times its cost in cement hauling alone. It was completed in October 1917, and operated around the clock during the construction of the dam, using one rented locomotive and six of its own.