FINAL UPDATE: IB/OB 39 cleared at Union and Kearny. Regular service resuming. Expect residual delays. (More: 9 in last 48 hours)

Central Subway Project
Project Introduction

The Central Subway Project will improve public transportation in San Francisco by extending the Muni Metro T Third Line through SoMa, Union Square and Chinatown. By providing a direct, rapid transit link between downtown and the existing T Third Line route on 3rd Street, the Central Subway will vastly improve transportation to and from some of the city's busiest, most densely populated areas.

When the Central Subway opens in 2022, T Third Line trains will travel mostly underground from the 4th Street Caltrain Station to Chinatown, bypassing heavy traffic on congested 4th and Stockton streets. Four new stations were built along the 1.7-mile alignment:

4th and Brannan Station at 4th and Brannan streets (street level)

Graphic of 4th and Brannan streets street-level platform

Yerba Buena/Moscone Station at 4th and Folsom streets (subway)

Graphic of Yerba Buena / Moscone Station from street level entrance

Union Square/Market Street Station on Stockton Street at Union Square (subway)

Graphic of Union Square / Market Street Station street level

Chinatown Station at Stockton and Washington streets (subway)

Graphic of Chinatown Station street level

Check out our video tour of the project alignment.

Project Implementation

Construction Phase

  • Building launch box for tunnel boring machines on 4th between Harrison and Bryant
  • Excavating tunnels by tunnel boring machines beneath SF
  • Building stations, surface tracks, and systems
  • Installing new track interchange at 4th and King and 4th Street surface tracks
  • Completing major excavation for Yerba Buena/Moscone Station and Union Square/Market Street Station and pivoting work toward interior construction

Testing Phase

  • Inspecting fire sprinklers installed in tunnels to ensure they respond to fire alarm activation
  • Testing emergency ventilation fans for adequate tunnel air supply and extraction
  • Conducting safety drills and developing contingency plans in the event of a passenger evacuation or first responders needing access to an incident in the tunnel
  • Verifying automatic train control system guides the automatic movement of light rail vehicles properly through tunnels
  • Assessing radio and data communication systems for effective delivery of audio and visual announcements to customers and automatic vehicle location data to the Transportation Management Center
  • Inspecting customer information system and certifying Metro audio announcements and displays are working correctly.

Revenue Service

Revenue service for the Central Subway is expected to begin in 2022. During the final phase, project staff will continue to engage our community partners and develop a communications plan to inform Muni customers of the first day of service.


Additional Resources

Project Timeline 
2011 - Spring 2021
Revenue Service
Spring 2022
Project Status
Implementation / Construction
Muni Metro train
SFMTA Accessibility icon
Bus Routes and Rail Lines
Stockton Street, 4th Street

Office Hours

Have a question about the Central Subway Project?  Stop by our construction office to get assistance from project staff during our Community Drop-In Office Hours:

Central Subway Project Office
530 Bush St. Suite 400 (4th Floor)
M-F 9am to 5pm


The Central Subway Project is funded by the Federal Transit Administration (FTA), the State of California, the Metropolitan Transportation Commission, the San Francisco County Transportation Authority and the City and County of San Francisco.

The majority of funding for the Central Subway Project is provided by the FTA’s New Starts program, with a total commitment over the life of the project of $948.4 million. An additional $41 million in federal funds is designated to the project as part of the U.S. Department of Transportation’s Congestion Mitigation and Air Quality Improvement Program, which supports environmental efforts for surface transportation and related projects. The federal funds allocated for the Central Subway Project cannot be redirected for investment in any other San Francisco projects.

The San Francisco Municipal Transportation Agency’s (SFMTA) baseline budget for the Central Subway Project remains at $1.578 billion. There has been no increase in the local funding commitment since original voter approval in 2003 of $126 million in Proposition B/K sales tax funds.

In total, about half of the funding for the entire Third Street Light Rail Transit Project is from federal sources, with the remaining half from state and local sources.  The Central Subway Project is one of the nation’s highest-rated projects in the FTA's New Starts program.

Project video(s)
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Contact Information
Enrique Aguilar