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 maneuver a shotcrete-spraying machine out of the top heading of the future station cavern entrance excavation. Central Subway | Project Advancement
July 15, 2016 - July 24, 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
Work to construct the tunnel invert is progressing near the Union Square area. 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.
Installation of utilities continues along 4th Street between Bryant to Townsend. A traffic detour for the installation sewer lines on the east side of 4th at Freelon continues. The tunnel concrete invert is being constructed. Regular day shift hours for other work at STS are 7am to 4pm. Sewer pile installation will begin at 4th and Townsend starting July 13 and will go until July 15, from 8pm to 5am. The bus stop at the southwest corner of 4th and Townsend will be shifted 80’ west from now until July 22, and work will be from 8pm to 5am. The bus stop at the southeast corner of 4th and Townsend will be shifted 60’ east from now until July 22, and work will be from 8pm to 5am. The bus stop at 5th & Townsend will be temporarily discontinued from July 11 through July 15; 7am to 3:30pm. Customers are advised to use the existing bus stop on Townsend near 4th Street.
Two sewer lines are being installed at 4th and Freelon. A temporary detour is in place, there. 
Holes dug to locate existing utilities are covered over at the end of the workday. Overview
- Sewer installation and traffic detour at Freelon
- Installation of Muni manhole and duct bank
- Utility installation
- High pressure water line installation
- Installation of 36" and 48" sewer lines
- Relocation of communication lines
- Sewer pile installation at 4th and Townsend
- 4th and Townsend bus stop temporary relocation (SW corner)
- 4th and Townsend bus stop temporary relocation (SE corner)
- 5th and Townsend bus stop temporarily discontinued
Details
What: Sewer installation work and traffic detour
Time: 7a.m. - 4p.m.
When: Monday to Friday
Where: 4th Street at Freelon
What: Installation of Muni manhole, duct bank, utility installation
Time: 7a.m.- 4p.m.
When: Monday to Friday
Where: Townsend Street between 4th Street and 5th Street
What: High pressure water line installation (night work)
Time: 7p.m - 5a.m.
When: Monday to Friday
Where: 4th Street and Townsend Street
What: Installation of 36" and 48" sewer lines
Time: 7a.m. - 4p.m.
When: Monday to Friday
Where: 4th Street between Bryant Street and Townsend Street (east side)
What: Relocation of communications lines
Time: 7p.m - 5a.m.
When: Monday to Friday
Where: 4th Street and Townsend Street intersection
What: Sewer pile installation
Time: 8p.m - 5a.m.
When: Through July 15
Where: 4th Street and Townsend Street intersection
What: 4th and Townsend bus stop temporary relocation
Time: 8p.m - 5a.m.
When: Until July 22
Where: Southwest corner of 4th and Townsend intersection. Bus stop shifted 80' west.
What: 4th and Townsend bus stop temporary relocation
Time: 8p.m - 5a.m.
When: Until July 22
Where: Southeast corner of 4th and Townsend intersection. Bus stop shifted 60' east.
What: 5th and Townsend bus stop temporary closure
Time: 7a.m - 3:30p.m.
When: Through July 15
Where: 5th Street and Townsend Street. Please use existing bus stop on Townsend near 4th. 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
- 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 last of temporary bracing has been removed from the mezzanine level of the station box. 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 a sewer force main is ongoing. The current traffic configuration from north of the station to Howard Street will remain. Excavation and temporary support strut installation continue below concourse level.
Wooden cribbing is prepared to be moved inside the station box. 
Workers have been cleaning the mezzanine level to prepare for finish wall construction. 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
With the completion of another section of the station roof deck, workers are installing waterproofing and sealing it. 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.
Night work to install utilities on Geary is has begun and may alter the traffic configuration on Geary. Jet-grouting work is completed and compensation grouting continues. Current activities include excavation for roof-deck on O’Farrell Street and restoration of sidewalk between Maiden Lane and Geary.
Concrete is being applied to create smooth finished walls in the north concourse. 
Excess concrete from the outer walls is being removed to prepare for finishing work and temporary supports. Overview
- Roof deck and concrete installation
- Compensation grouting
- Restoration of the southeast corner of the Union Square Garage
- Partial street and sidewalk restoration at the northeast corner of Geary Street and Stockton Street
- Night work to install utilities at Geary and Stockton
Details
What: Roof deck and concrete installation, rebar installation, utility work, excavation, and partial demolition of Union Square Garage
Time: 7a.m.- 11p.m.
When: Monday to Saturday
Where: Ellis Street to Post Street
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: Restoration of the southeast corner of the Union Square Garage
Time: 6a.m - 4p.m. (Monday to Friday) and 6a.m - 2p.m. (Saturday)
When: Monday to Saturday
Where: Geary Street and Stockton Street
What: Partial street and sidewalk restoration at the northeast corner of Geary Street and Stockton Street
Time: 6a.m - 4p.m. (Monday to Friday) and 6a.m - 2p.m. (Saturday)
When: Monday to Saturday
Where: Geary Street and Stockton Street
What: Night work to install utilities at Geary and Stockton
Time: 9p.m. to 5a.m.
When: Monday to Saturday
Where: Southeast corner of Geary and Stockton intersection
*For all activities, 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
- Stockton Street between Ellis Street and Post Street is closed to vehicular traffic
- One traffic lane open on O'Farrell through Stockton Street
Steel struts span across the inside of the headhouse to temporarily reinforce the walls, prior to construction of finished interior structural elements. 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 utility relocation, excavation of the headhouse, construction of the north access (emergency exit) shaft and construction of the Cross Cut Cavern. 
Workers discuss operations next to shotcrete spraying machinery. 
The movement of heavy equipment must be orchestrated at the bottom of the headhouse, where space is at a premium. 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 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.