UPDATE: Incident #NJudah train has been placed onto the sidetrack. Delay at Church and Duboce has cleared. OB https://t.co/vSxfPFyn2C (More: 41 in last 24 hours)

Central Subway Construction Update 11/20/15

Friday, November 20, 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. Rolls of green turf are being installed on Stockton in preparation for the 2015 Winter Walk Central Subway | Project Advancement

November 20-30, 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

After installing a high pressure water line on 4th street, the street has been restored Surface Station, Trackwork and Systems 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.

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. Workers reconstruct the concrete base slab under the street while conducting utility work at 4th and King
  A newly installed track exchange at 4th and King is now being used by N Judah and T  Third trains.  In 2019, these tracks will carry passengers from Mission Bay through SoMa to downtown and beyond.  Overview

  • Installation of Muni manhole and duct bank
  • Utility installation
  • Installation of high pressure water line
  • Tunnel drainage and invert slab construction


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 between Welsh Street and Brannan Street

What:  Tunnel drainage and invert slab construction
Time:  7a.m. - 4p.m.
When:  Monday to Friday
Where:  4th Street Tunnel

  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
    • Parking will be unavailable along the work area
    • Westbound lane on King Street closed during working  hours
    • Northbound lane on 4th Street closed during working hours

Long lengths of rebar lowered by crane are hand carried and put in place for the access portal 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.

Currently, excavation is taking place.

Heavy gauge rebar is being used in the construction of the slab which will eventually become the ceiling of the station box A worker uses a large wrench to screw rebar into slurry walls.  This helps tie in all the reinforcing steel once concrete poured for the mezzanine ceiling slab Overview

  • Excavation


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
    • Two lanes of traffic open on the east side of 4th Street

Workers are performing utility work in preparation for backfilling 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 until the November construction moratorium on Geary at Stockton for pile installation.

The team is preparing for Winter Walk 2015.  For more information, click here

Work to backfill and restore a section of Ellis Street at Stockton is underway Workers pour a slurry solution into a specific portion of the work site at Ellis and Market Street Overview

  • Installation of roof deck
  • Utility relocation and support
  • Excavation at north concourse
  • Partial demolition and remodeling of Union Square Garage
  • Rebar installation
  • Lightweight concrete installation as roadway backfill at north and south concourses


What: Roof deck, utility, excavation, rebar installation, partial demolition of Union Square Garage and lightweight concrete installation
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
  • Parking and Traffic Impact
  • Ellis Street will open to one lane eastbound with one parking lane on Wednesday, November 25 
  • 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 

A flagger signals when to lower and lift a bucket used in excavation. 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, trenching and connection of dewatering wells, and north access (emergency exit) shaft construction. 
  A crane operator carefully swings the steel bucket used to remove excavated material from the headhouse interior A bulldozer operator unloads material excavated from the headhouse interior into the steel "muck" bucket Overview

  • Excavation of station site
  • Connection of dewatering wells
  • Installation of temp bracing
  • North access (emergency exit) shaft construction


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:  North access (emergency exit) shaft construction
Time:  7a.m -5p.m.
When: Monday to Friday
Where: Stockton Street, Washington to Jackson 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 north access shaft construction
    • Parking will be unavailable during PG&E work
    • No parking on both sides of Stockton between Washington and Jackson
    • 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.