Berkeley Hills Tunnel

Berkeley Hills Tunnel

Company type	Infrastructure
Industry	Rail transport
Founded	1965
Headquarters	Oakland and Orinda , United States
Area served	San Francisco Bay Area
Products	Tunnel for Bay Area Rapid Transit (BART) trains

The Berkeley Hills Tunnel facilitates the passage of Bay Area Rapid Transit (BART) trains beneath the Berkeley Hills, connecting Rockridge station and Orinda station.

Design

Although the tracks run along the center median of California State Route 24 on both sides, the Berkeley Hills Tunnel provides a more direct route positioned north of the Caldecott Tunnel.

Excavated through diverse geological layers, predominantly consisting of soft and porous rock, the tunnel is intersected approximately halfway inside the western portal (Oakland side) by the seismically active Hayward Fault. It comprises two separate bores, each measuring in diameter, spaced apart, with emergency pedestrian cross-passages located every for evacuation purposes. At the eastern portal, a ventilation facility equipped with roll-down doors regulates airflow.

By 2017, ongoing fault creep had diminished the tunnel’s internal clearance, leading BART to initiate a $60 million repair and mitigation effort. This project involves removing portions of the tunnel walls and adjusting track alignment to counteract continual structural deformation.

Construction

Construction commenced in February 1965, with tunneling completed by March 1967 and overall completion by July 1968. The tunnel began revenue operations on May 21, 1973, coinciding with the launch of service on the Concord line. Material excavated during construction was utilized as fill for expanding the Port of Oakland.

Incidents

On December 4, 2013, a BART train encountered mechanical braking failure and conducted an emergency stop within the tunnel near Rockridge station. This incident resulted in eleven individuals receiving treatment for smoke inhalation.

See also

• List of tunnels in the United States