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. 
Crews have broken through into the subway tunnels inside the Yerba Buena/Moscone Station. Central Subway | Project Advancement
September 16 through September 25, 2016
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
Workers have repaved a former work area between Welsh and Freelon. 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.
Night work is ongoing on the east side of 4th Street between Bryant and King streets. Installation of utilities continues along 4th Street between Bryant to Townsend. Sewer slip lining work is underway on 4th Street between Townsend Street and King Street. Regular day shift hours for other work at STS are 7am to 4pm. The bus stop at the NE corner of 4th and Townsend will temporarily be relocated 140 feet to the east from 9/12 and 10/14. The bus stop at the SW corner of 4th and Bryant will be temporarily relocated 200 feet to the west between 7:00 am and 3:00 pm from 9/14 and 9/27.
Asphalt smoothing on 4th Street. 
Sewer reconstruction work at Bluxome. Overview
- Sewer improvement work
- Slip Lining of 78” Sewer
- Manhole installation
- Installation of Muni manhole and duct bank
- Utility installation
- Installation of 36" and 48" sewer lines
- Relocation of communication lines
Details
What: Sewer installation
Time: 7 p.m. - 5 a.m.
When: Monday to Friday
Where: 4th Street between Townsend Street and King Street
What: Slip Lining of 78" Sewer
Time: 7 a.m. - 5:30 p.m.
When: Monday to Saturday
Where: 4th Street between Townsend Street and King Street
What: 78" Sewer Improvement
Time: 7 a.m. - 5:30 p.m.
When: Monday to Saturday
Where: 4th Street at Brannan Street
What: 78" Sewer Offset Manhole Structure
Time: 7 a.m. - 5:30 p.m.
When: Monday to Saturday
Where: 4th Street at Bluxome Street
What: 78" Sewer Offset Manhole Structure
Time: 8 p.m. - 5:00 a.m.
When: Monday to Saturday
Where: 4th Street at Townsend Street
What: Installation of Muni manhole, duct bank, utility installation
Time: 7 a.m. - 4 p.m.
When Monday to Friday
Where: 4th Street at Brannan
What: Installation of 36" and 48" sewer lines
Time: 7 a.m. - 4 p.m.
When: Monday to Friday
Where: 4th Street between Bryant Street and Freelon Street
What: Relocation of communications lines
Time: 7 p.m. - 5 a.m.
When: Monday to Friday
Where: 4th Street at Brannan
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, including full closure of northbound 4th Street.
- Detours will be in place. The crosswalk may be disrupted. Alternative pedestrian walkways will be in place.
- A detour is in effect for access to Freelon Alley from 4th Street
- Parking will be unavailable in the work area on both sides of 4th Street
- Two lanes of traffic open on the west side of 4th Street
- Traffic impacts are in effect 24 hours a day
- Muni Impact
- 4th Street and Townsend Street northwest corner bus stop utilized by 30 Stockton, 45 Union, 47 Van Ness, and 83X Mid-Market Express bus stop relocated 100 feet west
- 4th Street and Townsend Street southwest corner bus stop temporarily relocated 80 feet west
- 5th Street and Townsend Street bus stop temporarily discontinued
- The bus stop at the NE corner of 4th and Townsend will temporarily be relocated 140 feet to the east from 9/12 and 10/14.
- The bus stop at the SW corner of 4th and Bryant will be temporarily relocated 200 feet to the west between 7:00 am and 3:00 pm from 9/14 and 9/27.
Workers have begun to excavate the platform level of the station box, breaking through the twin subway tunnels in the process. 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.
Excavation of the Yerba Buena/Moscone Station underneath 4th Street between Folsom and Clementina continues. The installation of utilities on 4th near Howard is ongoing. The current traffic configuration from north of the station to Howard Street will remain. Excavation continues below concourse level.
A supplies receiving platform at the Mezzanine level access portal. 
Workers continue to install waterproofing and finish walls inside the station box. Overview
- Excavation of the headhouse and station box
- Water line replacement and sewer installation
Details
What: Excavation of the headhouse and station box
Time: 7a.m - 7p.m.
When: Monday to Friday
Where: 4th Street between Howard Street and Folsom Street
What: Water line replacement and sewer installation
Time: 7a.m.- 4p.m.
When: Monday to Friday
Where: 4th Street between Howard Street and 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 4th Street
Workers use a large steel bucket to remove material excavated from inside the station. Union Square | Market Street Station
Work continues 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 and involves construction of a box frame structure within a trench excavation that is subsequently backfilled.
Installation of waterproofing and concrete on the plaza level of the Union Square Garage continues. There will be an increase in vehicles and activities as work at the southeast corner of Union Square ramps up. Night work at the Stockton and O'Farrell intersection will reduce O'Farrell to one lane through the work area. Current activities include station excavation and installation of temporary bracing under Stockton Street as well as on O'Farrell.
A worker maneuvers a large steel bucket before a crane operator lowers it into the station box. 
Workers are installing temporary steel bracing inside the station while excavating. Overview
- Compensation grouting
- Traffic lane reduction at O'Farrell and Stockton due to night work
- Station excavation and installation of temporary bracing
Details
What: Compensation grouting
Time: 6a.m - 4p.m. (Monday to Friday) and 6a.m - 2p.m. (Saturday)
When: Monday to Saturday
Where: Geary Street to O'Farrell Street
What: Traffic lane reduction at O'Farrell and Stockton due to night work
Time: 9p.m. to 5a.m.
When: Monday to Friday
Where: South side of the Stockton and O'Farrell intersection
*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
- One traffic lane open on O'Farrell through Stockton Street
Water is sprayed on a large jackhammer as a portion of the exterior slurry wall is removed. 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 headhouse, construction of the north access (emergency exit) shaft and tunnel, and construction of the Cross Cut Cavern.
Work to excavate the cross-cut cavern into the future station cavern is ongoing. 
A bulldozer collects excavated material at the south end of the headhouse. Overview
- Excavation of station site
- North access (emergency exit) shaft work
Details
What: Excavation of station site
Time: 24 hours
When: Monday to Saturday
Where: Stockton Street and Washington Street
What: North access (emergency exit) shaft work
Time: 7a.m.- 5p.m.
When: Monday to Friday
Where: Stockton Street, Washington Street to Jackson 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
- 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 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 and check out our blog.
Construction schedules are subject to change.