UPDATE: Incident #NJudah train has been placed onto the sidetrack. Delay at Church and Duboce has cleared. OB https://t.co/vSxfPFyn2C (More: 40 in last 24 hours)

Central Subway Construction Update 10/30/15

Friday, October 30, 2015 - 12:00am

Thank you for your interest in the Central Subway Project, which is a significant project in the history of San Francisco's public transportation network. This project is the first underground line to link the north and south corridors of the city, and will provide a direct connection to major retail, sporting and cultural venues while efficiently transporting people to jobs, educational opportunities and other amenities throughout San Francisco.

This is an exciting time as the San Francisco Municipal Transportation Agency's | Central Subway team works to construct a vital transportation link that, when open in 2019, will improve connectivity for the city.

Equipment and materials are stored within dormant portions of the work zone on 4th Street Central Subway | Project Advancement

October 30 - November 9, 2015

This notice provides a construction update and a look ahead for what to expect in the areas where we are building four new stations along the alignment. You’ll find information about work activities, traffic and transportation impacts taking place over the next two weeks at SoMa, Yerba Buena|Moscone, Union Square and Chinatown.

Construction schedules, bus routes, and stop locations are subject to change due to unforeseen conditions. Signs will be posted at affected stops to advise of service changes.

Our thanks goes out to the businesses, residents, shoppers, commuters, and all those who are touched by the Project, for their continued engagement as we work to extend the city's public transportation system.

The Central Subway Team

A high pressure water line that will be used by the fire department is being installed on 4th Street

Surface Station, Trackwork and Systems

The second phase of trackwork and transit signal priority upgrades has been scheduled for Veteran's Day Weekend, 10p.m. Friday November 6 through Saturday night, November 14.  This will be a 24 hour operation.    We will be hosting a Community Meeting to answer questions about this project on Wednesday, November 4 at the Bayview Library.   For meeting details, please review the invitation. The first phase of this project was completed over Labor Day Weekend.  The completion of this project will be a major milesstone in the construction of the Central Subway.  For more information, please visit the SFMTA's 4th and King site.

For the work along 4th Street between Bryant and King streets, a surface station will be built between Bryant and Brannan Streets. The construction team is working on upgrading utilities and trackwork on 4th Street between the portal at Bryant Street and the connection with the existing system at King Street.

The Bryant and 4th Street 47 Van Ness bus stop will be relocated 250 feet off the intersection through mid November. The following bus lines are affected:  8 Bayshore, 8 AX Bayshore Express, 8 BX Bayshore Express, 47 Van Ness. 

The installation of a 36" force main sewer  at 4th and Townsend is scheduled for weeknight evenings, through Thursday, November 5.  Hours of operation for each night are  8p.m. to 5a.m. The bus stop at the southwest corner of 4th and Townsend will be relocated 100 feet to the west during working hours. 

Current activities include utilities relocation, Muni manhole, duct bank, water line work from the water department, auxiliary water supply system, and sewer structure modification work.

Barricades mark where work is being done to tie in new pipes with existing utilities at 4th and King

A flagger ensures safety by monitoring traffic on 4th Street during construction


  • Installation of trackwork and signal priority transit upgrades
  • Installation of Muni manhole and duct bank
  • Utility installation
  • Installation of high pressure water line
  • Interior tunnel preparation
  • Installation of 36" force main sewer


What:  Installation of trackwork and transit signal priority upgrades
Time:  24 hour operation
When:  Friday, November 6 through Saturday, November 14

What: Installation of Muni manhole, duct bank, utility installation
Time: 7a.m. - 4p.m.
When: Monday to Friday
Where: Brannan Street between 4th Street and 5th, Street, Townsend Street to King Street

What:  Low pressure water line/AWSS
Time:  7a.m. - 4p.m.
When:  Monday to Friday
Where:  4th Street and Welsh Street

What:  Installation of 36" force main sewer
Time:  8p.m. - 5a.m.
When:  Monday to Friday
Where:  4th Street and Townsend Street

What to expect

  • Work may involve saw-cutting, potholing and jack-hammering on the roadway and sidewalk
  • Sidewalk access may be limited
  • Access will remain open for pedestrians and businesses
  • Muni Service Impact
  •  4th Street and Bryant Street bus stop relocated 250 feet off intersection affecting 8 Bayshore, 8 AX    Bayshore Express, 8 BX Bayshore Express and 47 Van Ness buslines
  • 4th and Townsend bus stop relocated 100 feet affecting 47 Van Ness busline
  • Parking will be unavailable along the work area
  • Parking and Traffic Impact
    • Parking will be unavailable along the work area
    • Eastbound lane on Bryant  Street closed  
    • Westbound lane on King Street closed during working  hours
    • Northbound lane on 4th Street closed during working hours
    • One lane of traffic closed on Townsend during evening hours
    • For parking and traffic impacts due to 4th and King trackwork, see attached notice

Steel beams called walers temporarily reinforce the walls of the structure during excavation

Yerba Buena | Moscone Station

4th Street from Howard to Folsom

Work along 4th Street between Howard Street and Folsom Street consists of construction of the underground Yerba Buena | Moscone Station. The cut and cover method known as a "top-down" or "bottom-up" approach involves construction of a box frame structure within a trench excavation that is subsequently backfilled.

Current activities include utility relocation and excavation.

Workers are building a concrete floor that will become the roof of the station platform.

A pipe extends through the temporary concrete slab, going out a ventilation shaft temporily constructed of what will eventually be emergency stairs


  • Installation of utilities
  • Excavation


What: Installation of Utilities
Time: 9a.m. - 5p.m
When: Monday to Friday
Where: 4th Street and Folsom Street

What: Excavation
Time:  7a.m.-7p.m.
When:  Monday to Friday
Where: Howard  Street to Folsom Street
  What to expect

  • Clementina Street is closed at 4th Street
  • The sidewalk on the west side of 4th Street is closed
  • Parking and Traffic Impact
    • One lane of traffic open on the east side of 4th Street

Corrugated steel sheets are being installed atop structural steel for the north concourse roof

Union Square | Market Street Station

For the duration of the project, you'll see work along Stockton Street between Ellis Street and Post Street. The construction of an underground Union Square|Market Street Station uses the cut and cover method known as a "top-down" or "bottom-up" approach involves construction of a box frame structure within a trench excavation that is subsequently backfilled.

Current activities include roof deck installation, demolition of the northwest corner of the Union Square Garage, utility relocation and compensation

Single-lane traffic continues through early November on Geary at Stockton for pile installation.

At the intersection of Ellis and Stockton, rebar is being installed over corrugated steel panels prior to pouring concrete and backfilling the site. 

A site inspector confers with a rebar specialist inside the southeast corner of the Union Square Parking Garage, where work to refit this section with a new vehicle ramp is underway


  • Installation of roof deck
  • Utility relocation and support
  • Excavation at north concourse
  • Partial demolition and remodeling of Union Square Garage
  • Rebar installation


What: Roof deck, utility, excavation, rebar installation and partial demolition of Union Square Garage
Time: 7a.m.-11p.m.
When: Monday to Saturday
Where: Ellis Street to Post Street
* Construction hours may be 24 hours a day, Monday to Saturday, Sunday work may be required What to expect

  • Local deliveries may access Maiden Lane from Post Street
  • Sidewalk access may be limited at times
  • Muni Service Impact
    • The bus stop for the 38 Geary Route on Geary Boulevard at Stockton Street is discontinued until further notice. Board bus on Geary Boulevard at Powell Street.
  • Parking and Traffic Impact
  • Ellis Street is closed to through traffic between Stockton and mid-block until mid-November. 
  • When Ellis reopens, vehicles will not be able to turn onto Market Street as part of the Safer Market Street project.  For more information, please visit https://www.sfmta.com/projects-planning/projects/safer-market-street
  • Stockton Street between Ellis Street and Post Street is closed to vehicular traffic 

Segments of steel I-beams just from the slurry walls of the station headhouse

Chinatown Station

The construction of an underground Chinatown Station uses the sequential excavation method (SEM) along Washington Street and Stockton Street. The SEM provides a high degree of flexibility during construction and makes it possible to control virtually all kinds of ground conditions, thereby greatly reducing the risks of construction. This method of tunnel construction is used worldwide for small to large openings in a variety of ground types ranging from rock to soil.

Sprayed concrete (shotcrete) and other supporting elements immediately after exposure, followed by installation of additional steel and shotcrete support elements until a safe stable opening is created will be used.

Current activities include utility relocation, excavation of the headhouse, and trenching and connection of dewatering wells. 

   A view inside the Chinatown station headhouse, with some temporary steel supports overhead

This drill rig is used to help waterproof the station headhouse by improving the surrounding soil with a mix of concrete like grout


  • Excavation of station site
  • Connection of dewatering wells
  • Installation of temp bracing


What: Excavation of station site
Time: 7a.m.- 7p.m.
When: Monday to Saturday
Where: Stockton Street and Washington Street

What:  Connection of dewatering wells
Time:  7a.m -5p.m.
When: Monday to Friday
Where: Stockton Street, Sacramento Street to Jackson Street

What:  Installation of temp bracing
Time:  7a.m -5p.m.
When: Monday to Friday
Where: Stockton Street

What to expect

  • Sidewalk access may be limited at times
  • Parking and Traffic Impact
    • Detours will be in place between the hours of 9p.m.and 5a.m. during dewatering wells installation
    • Parking will be unavailable during PG&E work
    • Washington Street:
      • remains closed between Stockton and Trenton streets
      • is converted into a two-way street between Powell Street and the construction zone

Connecting People. Connecting Communities.

Contact Us: If you have questions about construction or the Central Subway Project you can email us at central.subway@sfmta.com or call us at 415-701-4371.

For More Information: The Central Subway team posts frequent project updates on a variety of social media outlets. To find out more about the project and construction progress, follow us on Facebook, Twitter, or Flickr, and check out our blog.

Construction schedules are subject to change.