Although it operated as a common carrier, the Hetch Hetchy Railroad was built by the City of San Francisco to build the O'Shaughnessy Dam across Hetch Hetchy Valley as part of the city's water supply.

The dam was completed in 1923 and the railroad scaled back operations, selling some of its equipment, including #6, which was sold to Pickering Lumber Corporation in Standard, California.

[1] It is in a small collection of railroad equipment owned by the National Park Service near El Portal, California.

Number 6 was added to the National Register of Historic Places in 1978 as Hetch Hetchy Railroad Engine No.6.

This article about a property in Mariposa County, California on the National Register of Historic Places is a stub.