Twin Peaks Tunnel Improvements

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Project Introduction

Regular Service Resumed Saturday, August 25

Printable Rider Guide

Update: The two month closure to the Twin Peaks Tunnel ended on time. We understand the impact this had on your commute and neighborhood -- we thank you for your patience! Crews will continue to finish up final tasks in and around the tunnel through 2018.

With 100 years of service under its belt, Twin Peaks Tunnel needs extensive work to its interior to continue to operate safety and reliably for years to come. The tunnel's infrastructure, including the tracks, walls and drainage systems, must be maintained in a timely manner to keep up with the demands of the Muni system. Twin Peaks Tunnel is currently under a speed restriction, which slows down trains as they travel through. Replacing the tracks will lift the tunnel's speed restriction and keep trains running reliably through the system. Seismic reinforcements will better protect the tunnel's overall structure and stability. 

Construction began June 25 and will continue during a continuous closure of the tunnel for two months. During the closure, Forest Hill and West Portal stations will be closed, the K Ingleside will travel on a shortened route, and bus service will run for the L Taraval and M Ocean View lines. Nx buses will not operate during the closure, but additional N Judah trains will be in service. More details about getting around are below.

Cost Estimate
$40 million
Current Phase or Stage
Final Design
Predicted Completion
Winter 2019
Project Success
On budget
On schedule
Muni Metro train
New tracks and improved tunnel infrastructure
West Portal Avenue, Market Street, Junipero Serra Boulevard, Ulloa Street, Collingwood Drive

    Getting Around on Muni during this Summer's Two-Month Closure

    While the tunnel is closed for construction, buses will run for the M Ocean View and L Taraval lines. K Ingleside trains will run a shorter route between Sloat/St. Francis and Balboa Park. There will not be K Ingleside, L Taraval or M Ocean View trains running in Muni Metro. 

    • During weekday morning rush hour (6 a.m.-10 a.m.), Muni customers transferring from M buses or K trains to BART at Balboa Park can receive a free BART single-ride ticket, good for travel downtown through Embarcadero BART Station.
    • Forest Hill and West Portal stations will be closed for service. All outbound trains entering Castro Station heading outbound will switch back and head inbound.
    • Only S Shuttles and T Third trains will operate underground through Castro and Church stations. There will be increased service for N Judah, J Church, T Third and S Shuttle trains.

    K L M Service Map -- Begining June 25

    KLM Rider Guide Map

    Printable Rider Guide

    West Portal and Forest Hill Area Overview

    M Ocean View Bus and KJ Train Line Overview

    Line Specific Customer Information

    Cambios de Servico // 調整客運服務 // Mga Pagbabago sa Serbisyo

    K Ingleside trains 

    Trains will serve regular stops between West Portal Ave/Sloat/Portola and Balboa Park. Once K Ingleside trains reach Balboa Park, they will continue downtown as J Church trains.

    Customers headed downtown are encouraged to transfer to BART at Balboa Park.

    Train Frequency: every 8 minutes during peak, 15+ minutes early morning and evenings

    L Taraval buses

    Buses will serve regular stops between the zoo and Taraval & 17th Avenue.

    Temporary bus stops:

    • Taraval & 14th Avenue (transfer stop for 48 bus)
    • Taraval & Wawona (closest stop to West Portal Station)
    • Laguna Honda & Dewey (closest stop to Forest Hill Station)
    • Portola & O'Shaughessy (transfer stop for 36, 44, 52 and M buses)

    L buses will stop at both Castro and Church station where customers can transfer to and from Muni Metro underground. 

    L buses will not service the following stop locations:

    • 15th Avenue & Taraval (closest stop is 14th Ave & Taraval)
    • Ulloa & Forest Side
    • West Portal Station (closest stop is Taraval & Wawona)

    Bus frequency: every 5 minutes during peak hours, 15+ minutes during early morning and evening

    M Ocean View buses

    Buses will serve regular stops between San Jose & Geneva and St Francis Circle.

    Temporary bus stops:

    • Junipero Serra & Ocean (transfer location to K trains)
    • Portola & Vicente (closest to West Portal Station)
    • Portola & Laguna Honda (transfer location for 43 and 48 buses)
    • Woodside & Portola (transfer location for 36, 44 and 52 buses)

    M buses will stop at Castro and Church stations where customers can transfer to and from Muni Metro underground. 

    M Buses will not service the following stops:

    • West Portal Station (closest stop at Portola & Vicente)
    • Forest Hill Station

    Customers headed downtown are encouraged to transfer to BART at Balboa Park

    Bus frequency: every 5 minutes during peak hours, 15+ minutes during early morning and evening

    Forest Hill (FH) Shuttle Bus

    The Forest Hill Shuttle Bus will connect between L and M buses and K trains. It will also be a key way to travel between the Forest Hill Station area and the West Portal corridor.

    The shuttle will stop at the following locations:

    • Forest Hill Station
    • Laguna Honda & Dewey
    • West Portal & Vicente
    • West Portal Ave/Sloat/Portola

    Bus frequency: every 15+ minutes.

    OWL Service 

    L OWL and 91 OWL buses will be rerouted via 14th Ave and Vicente. Transfer between 91 and L buses at West Portal Ave & Vicente.

    Nx Express Service

    Buses will not operate during tunnel construction. Use N trains instead.


    The following lines will have reroutes: 35, 48, 57, 91 Owl, L Owl. Signage will be posted at affected stops.

    Cambios de servicio

    La construcción empezará este verano e incluirá un cierre completo del túnel por un periodo de hasta dos meses. Durante el cierre del túnel las estaciones del Metro de Muni de Forest Hill y West Portal estarán cerradas. El tren K Ingleside tendrá una ruta más corta, y habrá servicio sustituto por autobús para las líneas de tren L Taraval y M Ocean View.

    • Comenzando en Junio 25, el túnel Twin Peaks y las estaciones West Portal y Forest Hill cerrarán por dos meses.
    • Los trenes K operarán una ruta más corta entre Sloat/St. Francis y Balboa Park. Tan pronto los trenes K Ingleside lleguen a Balboa Park, desde ahí continuarán al centro de la ciudad como trenes J Church.
    • Autobuses L operarán entre el SF Zoo y la estación Church en vez de trenes.
    • Autobuses M operarán entre Balboa Park y la estación Church en vez de trenes.
    • Autobuses L y M pararán en las estaciones Castro y Church, donde los clientes podrán transferirse desde o hacia el Muni Metro subterráneo.
    • A los clientes de M y K dirigidos al centro de la ciudad se les recomienda transferirse a Bart en Balboa Park. Boletos de Bart gratis a Embarcadero estarán disponibles L-V, 6am-10am.
    • El autobús shuttle Forest Hill conectará Forest Hill a West Portal.
    • Para la estación de Forest Hill utilice el autobús L o el autobús shuttle Forest Hill solamente.
    • Para la estación de West Portal, use el autobús M o el autobús shuttle Forest Hill solamente.


    工程將於2018年夏季開始, 其間需要關閉地鐵隧道達兩個月之久。地鐵關閉期間, Forest Hill和West Portal站將停止使用, K線街車將縮短旅程, 巴士將代替L線和M線街車運行。 K, L 及M線街車的詳細運行情況可在交通局網頁上查詢

    • 從6月25日起, 持續兩個月, 雙峰山隧道(Twin Peaks Tunnel)兩端的West Portal和Forest Hill地鐵站將關閉。
    • K線街車將縮短行程, 只在Sloat夾St. Francis街和Balboa Park之間運行。K線街車行駛到Balboa Park時, 將轉變成J線街車駛往市中心。
    • L線街車將由巴士代替在動物園和Church站之間運行。
    • M線街車將由巴士代替在Balboa Park和Church站之間運行。
    • L線巴士和M線巴士將在Castro和Church站停靠, 以便讓乘客轉乘地鐵。
    • 搭乘L線街車和M線街車的乘客最好在Balboa Park轉乘灣區捷運(BART) 。前往Embarcadero的BART免費票將在週一至週五早6點到早10點之間有效。
    • Forest Hill穿梭巴士將在Forest Hill 和West Portal之間運行。
    • 前往Forest Hill站, 請只搭乘L線巴士或Forest Hill穿梭巴士。
    • 前往West Portal站, 請只搭乘M線巴士或Forest Hill穿梭巴士。

    Mga Pagbabago sa Serbisyo

    Sisimulan ang konstruksiyon habang nakasara ang tunnel sa summer 2018/tag-init at tatagal ito ng dalawang buwan. Habang nakasara ito, isasara rin ang mga estasyon ng Forest Hill at West Portal, ang ruta ng K Ingleside ay paiikliin, at ang serbisyo ng bus ay tatakbo sa mga linya ng L Taraval at M Ocean View.

    • Dalawang buwan simula Hunyo 25, sarado ang Twin Peaks Tunnel, West Portal Station at Forest Hill Station.
    • Tatakbo ang pinaikling ruta ng K train sa pagitan ng Sloat/St. Francis at Balboa Park. Kapag nakarating na ang K Ingleside sa Balboa Park, tutuloy ito downtown bilang tren sa linya ng J Church.
    • Ang L Bus ang patatakbuhin sa halip na mga tren sa pagitan ng SF Zoo at Church Station.
    • Ang M Bus ang papatakbuhin sa halip na mga tren sa pagitan ng Balboa Park at Church Station
    • Ang mga L at M Bus ay titigil sa mga estasyon ng Castro at Church kung saan maaari mag-transfer/lumipat sa Muni Metro underground.
    • Ang mga pasahero ng M at K na papuntang downtown ay hinihikayat na lumipat sa Balboa Park BART. Available ang mga libreng Bart tiket Lunes hanggang Biyernes, 6am-10am.
    • Ikokonekta ng Forest Hill Shuttle ang mga estasyon ng Forest Hill at West Portal.
    • Para sa Forest Hill Station, gamitin lamang ang L Bus o ang Forest Hill Shuttle.
    • Para sa West Portal Station, gamitin lamang ang M bus o Forest Hill Shuttle. 
    Project video(s)
    Project Details, History or Features

    SFMTA will be working in the tunnel to address the following improvements:

    • Replacing the existing light rail tracks and track fittings
    • Replacing the machines which operate the track switching mechanisms
    • Replacing the tunnel's drainage system
    • Adding crossover tracks for operation flexibility
    • Seismic upgrades to the original east portal of Twin Peaks Tunnel (Eureka Valley Station)
    • Improving structure support between West Portal and Forest Hill stations
    • Improvements to fire suppresion system at West Portal Station
    • Repairing areas on concrete walls and reinforcements

    Construction Staging

    Staging areas on both sides of the tunnel will be used to store materials and equipment, and ensure that crews have the nessesary materials at hand to work quickly and efficienty.

    The staging area on the West Portal side of the tunnel will be on Junipero Serra between Sloat Boulevard and Ocean Avenue, along both sides of the K Ingleside Muni tracks (see image below). The staging area will not affect transit and vehicle traffic-- trains will run regular service and Junipero Serra will maintain existing traffic lanes. To accommodate the staging area, parking on the east and west sides of Junipero Serra will be temporarily removed until construction is complete.

    The MTA-owned parking lot located at Ocean Avenue and Junipero Serra will also be used for storing vital materials and equipment for the duration of construction. Streets around the parking lot will remain open and accessible.

    Median space along K Ingleside tracks on Junipero Serra between Ocean and Sloat will be used for staging during the construction. The Lakeside Parking Lot at the corner of Ocean and Junipero Serra will also be used for storage and staging until construction is complete.                                                                                                                                                                                                                                                                                                                                                                                                   

    On the Castro side of the tunnel, the areas in front of the original Twin Peaks Tunnel portals on Market Street will be used as a staging area (see image below). Bus stops affected by the staging area will be temporarily relocated during construction. The right turn onto Market Street from Collingwood Street will not be accessible. Vehicles on Collingwood headed to Market Street would need to turn onto 18th Street and Castro Street. All sidewalks and pathways leading to Castro Muni station will remain open to pedestrians.​

    Staging area is along Market Street between Collingwood and Castro, outside of the original tunnel portals

    Twin Peaks Tunnel History

    Twin Peaks Tunnel was a vital component to the growth of San Francisco and the expansion of the Muni system. After the 1906 earthquake, San Francisco's infrastructure developments grew, and city officials looked to expand the growth to the outer areas of the city, especially the undeveloped land west of Twin Peaks. In order to effectively reach the west side, city engineer Michael O’Shaughnessy decided to drill straight through the mountains. In February 1918, the Twin Peaks Tunnel opened, connecting the end of Market Street, at Eureka Valley station, to developing neighborhoods in Forest Hill and West Portal. K Ingleside and L Taraval shuttles began running soon after the tunnel opened. M Ocean View service began in 1925 and expanded as neighborhoods expanded. A bond issue passed in 1962 to build the regional BART system also included funding to build subway tunnels for Muni. The new Muni tunnels were connected to the Twin Peaks Tunnel, creating Castro station and providing a more streamlined service through the city. Today, Twin Peaks Tunnel carries over 80,000 Muni customers daily.

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      Contact Information
      Phillip Pierce