UPDATE: The OB 29 has resumed its regular route through the area of Beverly and Holloway. https://t.co/h7vf1DxYJX (More: 10 in last 48 hours)

Central Subway Construction Update 5/11/18

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. A large, rolling scaffolding structure is being assembled at the south end of the Chinatown track crossover cavern. Central Subway | Project Advancement

May 11 through May 20, 2018

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 go 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

Crews have backfilled a shallow trench between the dual surface trackways to prepare for a future concrete pour. Surface Station, Trackwork and Systems Work along 4th Street between Bryant Street and King Street includes construction of a surface station between Bryant Street and Brannan Street. The construction team is upgrading utilities and trackwork on 4th Street between the tunnel portal at Bryant Street and the connection with the existing light rail system at King Street.

Construction of the 4th and Brannan surface station platform is ongoing.  Track installation work is ongoing between Brannan and King.  Some lane closures may also occur at night.  Regular day shift hours are from 7am to 4pm.  Looking up the northbound tunnel, crews have constructed tunnel walkways up to the S-curve under the Market Street subway. Workers have installed additional concrete forms at the 4th and Brannan Station site to prepare for platform construction. Overview

  • Utility upgrade and relocation
  • Night work on 4th between King and Bryant
  • Street and sidewalk restoration

Details

What: Night utility work on 4th between King and Bryant
Time: 8 p.m. - 5:00 a.m.
When: Monday to Saturday
Where: 4th Street between King and Bryant
What: Utility installation and street restoration work

What: Street and sidewalk restoration
Time: 7 a.m. - 5:30 p.m.
When: Monday to Saturday
Where: 4th Street between King and Bryant

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 
  • Parking and Traffic Impact
    • Partial lane closures on 4th Street between Townsend and King streets.
    • Parking will be unavailable in the work area on both sides of 4th Street.
    • Two lanes of traffic open on 4th Street, one on the east side and one on the west.
    • Traffic impacts are in effect 24 hours a day.
  • Muni Impact
    • No scheduled impacts at this time.

Crews have been constructing massive rebar cages for headhouse roof slab beams at the Yerba Buena/Moscone Station site. 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 involves construction of a box frame structure within a trench excavation that is subsequently backfilled.

Sewer replacement work continues at night at 4th and Howard streets.  Work hours are 8 p.m. to 5 a.m.  Eastbound traffic on Folsom may be impacted.  Three through lanes are in place southbound 4th Street. Westbound traffic on Howard Street may be impacted.

Multiple rows of rebar cages which will reinforce future roof slab beams can be seen from Clementina looking southeast. An instructor discusses fall safety and body harness protection inside the upper level of the Yerba Buena/Moscone station box. Overview

  • Sewer replacement work at 4th and Howard
  • Installation of headhouse and station interior elements

Details

What: Sewer replacement work
Time: 8pm - 5am
When: Monday to Friday
Where: 4th and Folsom and 4th and Howard Street intersections.

What: Installation of headhouse and station interior elements
Time:  5am - 3:30pm
When: Monday to Friday
Where: 4th Street between Howard Street and Folsom Street What to expect

  • Clementina Street is closed for traffic and pedestrians through to 4th Street
  • The sidewalk on the west side of 4th Street is closed south of Howard
  • Parking and Traffic Impact
    • Two lanes of traffic open on the east side of 4th Street, may be reduced to one lane at night between 9 pm and 5 am Monday through Friday.
  • Muni Impact
    • No scheduled impacts at this time

    A crew assemble scaffolding and formwork to construct wale encasements on the mezzanine level of the Union Square/Market Street station box. Union Square | Market Street Station

    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 and involves construction of a box frame structure within a trench excavation that is subsequently backfilled. Some work continues at night along Stockton Street between Ellis Street and Post Street.

    One lane on the south side of Ellis Street is open at all times for eastbound traffic.  Parking garage access is open on north side of Ellis Street. Utility installation and street restoration work are ongoing north of the intersection of Stockton and Market streets.  The installation of waterproofing, structural steel, and concrete at the southeast corner of the Union Square Garage continues.  There will be a continued presence of vehicles and equipment as work at this location continues.  Installation of internal structural elements and utilities is ongoing under Stockton Street as well as the northeast corner of Stockton and O'Farrell.

    Workers line up at the staff elevator following the end of a shift inside the fan level of the north concourse under Geary and Stockton. A team assembles complex support scaffolding along the west wall of the Union Square/Market Street station box. Overview

    • Utility work on Stockton north of Ellis
    • Installation of internal structural elements and temporary bracing
    • Union Square Garage (north station entrance) structural installation

    Details

    For all activities, construction hours may be 24 hours a day, Monday to Saturday, Sunday work may be required What to expect

    • Sidewalk access may be limited at times
    • Parking and Traffic Impact
      • Stockton Street between Ellis Street and Geary Street is closed to vehicular traffic
    • Muni Impact
      • No scheduled impacts at this time.

    Multiple layers and rows of waterproofing are being installed and sealed together at the south end of the Chinatown track crossover cavern. Chinatown Station The construction of Chinatown Station used the sequential excavation method (SEM), providing a high degree of flexibility and control over 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.  Excavation of the Chinatown Station site was completed in February 2018.

    Current activities include construction of the north and south platform caverns, as well as the track crossover cavern, and invert base slab of the station headhouse.  A pedestrian walkway is open on the north side of Washington connecting Trenton and Stockton. A crew installs rebar and cuts specific pieces to length as part of Chinatown Station platform cavern invert construction. Two men on a inspect sheets of waterproofing near the southbound tunnel entrance of the Chinatown track crossover cavern. Overview

    • Construction of the base slab inside the station headhouse
    • Construction of the station platform and track crossover cavern interiors

    Details

    What: Headhouse, platform cavern, and track crossover cavern construction
    Time: 24 hours
    When: Monday to Saturday
    Where: Stockton Street and Washington Street What to expect

    • Sidewalk access may be limited at times
    • Parking and Traffic Impact
      • No parking on both sides of Stockton Street between Washington Street and Jackson Street
      • One lane of traffic on both sides of Stockton Street between Washington Street and Jackson Street
      • Washington Street:
        • remains closed between Stockton Street and Trenton Street, except to pedestrians
        • is converted into a two-way street between Powell Street and the construction zone
    • Muni Impact
      • No scheduled impacts at this time.

    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 leave a message 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.

    Construction schedules are subject to change.