Twin Peaks Tunnel

West Portal Station, at the western end of the Twin Peaks Tunnel
Overview
Line	K Ingleside   L Taraval   M Ocean View   T Third Street
Location	San Francisco, California
System	Muni Metro
Start	Eureka Station
End	West Portal Station
No. of stations	3 (2 open, 1 closed)
Operation
Owner	SFMTA
Operator	San Francisco Municipal Railway
Character	Light rail
Technical
Line length	2.27 mi (3.65 km)[1]
No. of tracks	2
Track gauge	4 ft 8+1⁄2 in (1,435 mm)
Electrified	Overhead lines, 600 V DC
Tunnel clearance	25 ft (7.62 m)[1]

The Twin Peaks Tunnel is a 2.27-mile (3.65 km)^[1] long light rail transit/streetcar tunnel in San Francisco, California, United States, running under Twin Peaks. When it was opened on February 3, 1918,^[2] it was one of the longest railway tunnels in the world (Paris Métro's line 1, opened in 1900, beat it by a few miles, as did some of the London Underground lines). It was the longest U.S. railway tunnel west of New York City.^{[citation needed]} The service through it has evolved from streetcars into light rail, and while there are longer light-rail tunnels elsewhere (such as Portland's Robertson Tunnel), the Twin Peaks Tunnel remains one of the world's longest streetcar or light-rail tunnels.^{[citation needed]} It runs from the intersection of Market Street at Castro Street in the east to the West Portal neighborhood in the west. There are two stations along the tunnel, Forest Hill Station, near the western end, and the now disused Eureka Station, near the eastern end.

When the Muni Metro system and Market Street Subway was built, it was connected to the Twin Peaks Tunnel to be used by the K Ingleside, L Taraval and M Ocean View lines. The Eureka Station was closed, and the Metro lines stop at the nearby Castro Street Station instead. The original eastern entrance to the tunnel in the middle of Market Street at Castro was removed and new ones were placed on the side of the street further up the block, though no Metro or streetcar lines use them in regular service (they were used during construction of the Market Street subway and are occasionally used in non-revenue service such as rerouting trains around construction projects). Instead, trains continue directly from the Market Street Subway into the tunnel, without going above ground. A new station with high platforms, West Portal Station, was also built for the Metro lines at the western end of the Twin Peaks Tunnel.

In 2011, the Niles Silent Film Museum in Niles, California discovered a 19-minute silent film produced by Baldwin and Howell Real Estate Co. of San Francisco. (See External Links.)

• Sunset Tunnel

• Silent film by SF real estate company of construction of tunnel (1914-17)

37°44′27.27″N 122°27′57.58″W / 37.7409083°N 122.4659944°W / 37.7409083; -122.4659944