Berkeley Hills Tunnel

Berkeley Hills Tunnel

Overview
Line	Pittsburg/Bay Point–SFO/Millbrae
Location	Berkeley Hills, California
Coordinates	Oakland portal: 37°51′05″N 122°14′17″W Orinda portal: 37°52′29″N 122°11′16″W
System	Bay Area Rapid Transit
Start	Rockridge Station, Oakland
End	Orinda Station, Orinda
No. of stations	None
Operation
Opened	May 21, 1973
Owner	San Francisco Bay Area Rapid Transit District
Operator	San Francisco Bay Area Rapid Transit District
Character	Rapid transit
Technical
Line length	3.2 mi (5.1 km)
No. of tracks	2
Track gauge	5 ft 6 in (1,676 mm) (Indian gauge)
Electrified	Third rail, 1000 V DC
Tunnel clearance	22 feet (6.7 m)

The Berkeley Hills Tunnel is a tunnel which carries Bay Area Rapid Transit's Pittsburg/Bay Point–SFO/Millbrae line through the Berkeley Hills between the Rockridge and Orinda stations. While the tracks run in the median of California State Route 24 on both sides of the tunnel, the Berkeley Hills Tunnel allows the tracks to take a straighter alignment offset to the north of the Caldecott Tunnel.

It bores through the Berkeley Hills east of Berkeley and Oakland a distance of 3.2 miles (5.1 km) through a variety of rock strata, most of which are soft and porous. The earthquake-active Hayward Fault bisects the tunnel about 1,000 feet (300 m) inside the west portal (Oakland side). There are 2 bores, each about 22 feet (6.7 m) in diameter, spaced 50 feet (15 m) apart. Pedestrian cross-tunnels are spaced every 1,000 feet (300 m) for emergency evacuation in case of fire, etc. There is a ventilation structure at the east portal with roll-down doors that can close off the tunnel end to allow air to be sucked out or blown in. Boring was completed in February 1967 after 465 work days. The tunnel was opened for revenue service in 1973.

Material removed in the construction of the tunnel was used as fill for a concurrent expansion of the Port of Oakland.

See also

• Caldecott Tunnel — large motor vehicle tunnel, running approximately parallel to the Berkeley Hills Tunnel
• List of tunnels in the United States