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. 
Workers assemble a massive rebar cage against the west wall of the Yerba Buena/Moscone station box, as part of interior wall construction. Central Subway | Project Advancement
August 18 through August 27, 2017
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
Sewer tie-in work is underway at 4th and Welsh. 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.
Some lane closures may occur at night. Night work is ongoing on 4th Street between Bryant and King Streets, between 8:00 PM and 5:00 AM. Utility installation and upgrade work continues along 4th Street between Bryant and King, and regular day shift hours are from 7am to 4pm. 
Workers place asphalt to ease vehicle transitioning between paved and unpaved sections of the street. 
A portion of the roadway on 4th north of Welsh has been restored. Sidewalk restoration is underway. Overview
- Night work on 4th between King and Bryant
- Street and sidewalk restoration
- Temporary bus stop relocation at Bryant and 4th
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: Pavement renovation
Time: 7 a.m. - 5:30 p.m.
When: Monday to Saturday
Where: 4th Street between King and Welsh
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
Looking north from the station box into the northbound tunnel, rail is being installed inside the station box under 4th Street. 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 at 4th and Howard has resumed. Utility work at 4th and Folsom is ongoing and may reduce 4th Street to one lane between the hours of 8 pm and 5 am, Monday through Friday. Curb ramp and pavement renovation work is underway on Clementina. Night work on Folsom and 4th is permitted from 8pm to 5am Monday through Friday and will have a two month duration.
Night work to excavate and inspect utilities may occur at 4th and Howard between 9 pm and 5 am. The current traffic configuration from north of the station to Howard Street will remain, but may change in the coming weeks.
Concrete forms for the concourse level floor slab are being constructed atop heavy-duty scaffolding in the headhouse. 
Workers construct concrete forms and install rebar as part of station platform construction inside the station box. Overview
- Sewer replacement work
- Night work at Folsom and 4th.
- Installation of headhouse and station interior structural elements
- Roadway and sidewalk restoration on 4th south of Howard
- Utility potholing at 4th and Howard
Details
What: Sewer replacement work
Time: 7am - 3pm
When: Monday to Friday
Where: 4th and Howard Street intersection.
What: Night work at Folsom and 4th
Time: 8pm - 5am
When: Monday to Friday
Where: Folsom Street west of the intersection at 4th, and at the 4th Street intersection.
What: Installation of headhouse and station interior structural elements
Time: 7am - 7pm
When: Monday to Friday
Where: 4th Street between Howard Street and Folsom Street
What: Roadway restoration on the west side of 4th Street south of Howard
Time: 7am - 4pm
When: Monday to Friday
Where: 4th Street between Howard Street and Folsom Street
What: Utility potholing at 4th and Howard
Time: 9pm - 5am
When: Monday to Friday
Where: 4th and Howard intersection
What: Curb installation work
Time: 7am - 7pm
When: Monday to Saturday
Where: Clementina between 4th and 5th 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
- No scheduled impacts at this time
Massive strands of rebar bundled together are lowered into the station box, where they are received by waiting workers and installed as part of invert slab construction. 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.
Potential nighttime closure of Ellis between Powell and Stockton to vehicular traffic may be in effect from 9 pm to 5 am 7 days a week, to conduct roadway restoration work. 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. Station excavation and installation of structural steel bracing is ongoing under Stockton Street as well as on O'Farrell.
Two workers ferry supplies and materials inside the station box using a wheelbarrow. 
Crew members keep the worksite clean and free of debris as much as possible. Overview
- Utility work at the Ellis and Stockton intersection
- Utility work at the Geary and Stockton intersection
- Station excavation and installation of temporary bracing
- Union Square Garage plaza level concrete and structural installation
- Union Square Garage plaza temporary bracing installation
- Nighttime closure of Ellis between Powell and Stockton
Details
What: Nighttime closure of Ellis for roadway restoration work
Time: 9p.m - 5a.m.
When: 7 days a week
Where: Ellis Street between Powell and Stockton
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
- Ellis may be closed to vehicular traffic at night between 9 pm and 5 am 7 days a week
- Stockton Street between Ellis Street and Geary Street is closed to vehicular traffic
- Muni Impact
- No scheduled impacts at this time.
Workers using a special drill rig inside the top heading of the north platform cavern ready a section of drill casing to be installed. 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 are applied and installed promptly after exposing ground, which provides a safe and stable opening.
Current activities include excavation of the north and south platform caverns. A pedestrian walkway is open on the north side of Washington connecting Trenton and Stockton.
Workers use a drill rig to improve soil conditions for the next push of excavation inside the south platform cavern. 
Slurry used as part of drilling operations is collected at a holding area inside the station headhouse. Overview
- Excavation of station headhouse
- Excavation of the north and south platform caverns
Details
What: Station site excavation
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.