Hetch Hetchy Railroad 6, Steam locomotive in El Portal, United States.

Hetch Hetchy Railroad 6 is a standard gauge three-truck Shay locomotive built by Lima Locomotive Works in November 1921. It is the only three-truck Shay of the four the railroad operated and weighs more than twice as much as the others. It is displayed in a small collection of railroad equipment owned by the National Park Service near El Portal, California.

Built in 1921 by Lima Locomotive Works, this locomotive helped construct the Hetch Hetchy Dam in California. It was one of four Shay-type machines used for this major engineering project.

This locomotive represents early 20th-century railroad engineering, operating as a common carrier while supporting San Francisco's water infrastructure development.

The locomotive is now displayed as a static exhibit near El Portal and can be viewed from outside. The location is easy to access and offers a look at an important piece of railroad history.

Number 6 was the only three-truck Shay on the Hetch Hetchy Railroad and weighed more than twice as much as the line's other Shays. After the dam was finished in 1923 it was sold to Pickering Lumber Corporation in Standard, California, and hauled logs until its retirement in 1958.