Twin Peaks Tunnel at Forest Hill station
|Location||San Francisco, California|
|Start||Eureka Station (closed)|
|End||West Portal Station|
|No. of stations||3
(2 open, 1 closed)
|Opened||February 3, 1918|
|Owner||San Francisco Municipal Transportation Agency|
|Operator||San Francisco Municipal Railway|
|Character||Underground subway tunnel for light rail/streetcar system|
|Line length||2.27 mi (3.65 km)|
|No. of tracks||2|
|Track gauge||(standard gauge)|
|Electrified||Overhead lines, 600 V DC|
|Tunnel clearance||25 ft (7.6 m)|
The Twin Peaks Tunnel is a 2.27-mile (3.65 km)-longlight rail/streetcar tunnel in San Francisco, California. The tunnel runs under the Twin Peaks and is used by the K Ingleside/T Third Street, L Taraval, M Ocean View, and S Castro Shuttle lines of the Muni Metro system.
The tunnel was opened on February 3, 1918, and was the world's longest of its kind at the time. The eastern entrance to the tunnel is located near the intersection of Market and Castro streets in the Castro neighborhood, and the western entrance is located at West Portal Avenue and Ulloa Street in the West Portal neighborhood.
The service through the tunnel 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. There are two stations along the tunnel, Forest Hill near the western end, and the now disused Eureka station near the eastern end.
When the Muni Metro system and Market Street Subway were built, they were 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 entrances were placed on the sides 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.
Forest Hill and Eureka stations were originally constructed with low platforms, as streetcars of that era had steps to load passengers from street level. However, the six new Market Street Subway stations were built with high-level platforms for speedier level boarding onto the new Boeing LRVs. West Portal station, which was originally a surface stop outside of the tunnel's western entrance, was rebuilt as a high-platform station located just inside of the entrance. With Eureka station permanently closed, Forest Hill was left as the only low-platform station on the Muni Metro subway. Muni soon modified the station with high-level platforms, with completion in 1985.
Around 2014, with the tunnel nearing a century of continuous use, Muni began planning a major track replacement project in the tunnel - the first since 1975. The project includes the replacement of all rails and ties in the tunnel with new rails directly fixed to concrete pads, the installation of two pairs of crossovers (one near West Portal, the other just east of Forest Hill), replacement of existing switches to the unused eastern portals, a structural refit of the former Eureka station area, replacement of the overhead wires, and a number of other repairs and improvements. The work will lift an existing 25 miles per hour (40 km/h) speed limit through the tunnel. Noise reduction techniques from a similar project on the Sunset Tunnel in 2016 will be used.
The construction contract was awarded on April 5, 2016. The project was originally planned to begin in late 2016, but has suffered a series of delays. It was delayed from April 2017 to mid-2017 (with a completion date of mid-2018) in March 2017 to allow for "additional technical analysis" of the tunnel. In June 2017, the project was indefinitely delayed after the construction contract was terminated. Muni and the contractor could not agree on a new schedule and costs to minimize disruptions to riders; the project duration increased from 460 days to 807 days and the cost to $48 million, and Muni staff recommended the contract be terminated. The SFMTA released a Request for Qualifications in October 2017, and bidding opened for the $35.5 million project in November.
Media related to Twin Peaks Tunnel at Wikimedia Commons