Franklin Tunnel

Franklin Tunnel is a railway tunnel near Martinez, California. It carries the BNSF Railway Stockton Subdivision under the Briones Hills between Glen Frazer and the railroad's approach to the San Francisco Bay. It was built by the San Francisco and San Joaquin Valley Railroad just prior to the company's acquisition by the Atchison, Topeka and Santa Fe Railway. It opened for service in 1900 as the company's longest tunnel.

The tunnel is 5680 ft in length, with a maximum depth of 300 ft below the summit. Its cross section is 18 ft tall and 13 ft wide, carrying a single track.

The tunnel was closed for several weeks in early 1907 as a persistent fire ate away at the supporting timbers, causing a cave-in.