Central Subway


The Central Subway is an extension of the Muni Metro light rail system under construction in San Francisco, California, from the Caltrain commuter rail depot at 4th and King streets to Chinatown, with stops in South of Market and Union Square.
The subway is the second phase of the San Francisco Municipal Transportation Agency's Third Street Light Rail Project. The first phase opened to the public as the T Third Line in 2007. Ground was broken for the Central Subway on February 9, 2010. Tunnel boring for the Central Subway was completed at Columbus and Powell Street in the North Beach neighborhood of San Francisco on June 11, 2014. Originally set to open in late 2018, the Central Subway is projected to open to the public in late 2021. With the addition of the Central Subway, the T Third Line is projected to become the most heavily ridden line in the Muni Metro system by 2030.
The extension will serve major employment and population centers in San Francisco that are underserved by rapid transit. SoMa is home to the headquarters of many of San Francisco’s major software and technology companies, and substantial residential growth is projected there. Union Square, located in the city's downtown, is a primary commercial and economic district. Chinatown is the most densely populated neighborhood in the city. The Central Subway will connect these areas to communities in eastern San Francisco, including Mission Bay, Dogpatch, Bayview-Hunters Point and Visitacion Valley. The project was initiated after the Embarcadero Freeway was torn down following the 1989 Loma Prieta earthquake, when activist Rose Pak "almost single-handedly persuaded the city to build" the Central Subway to compensate Chinatown for the loss of the fast cross-town connection.
The budget to complete the Central Subway is $1.578 billion. The project is funded primarily through the Federal Transit Administration’s New Starts program. In October 2012, the FTA approved a Full Funding Grant Agreement, the federal commitment of funding through New Starts, for the Central Subway for a total amount of $942.2 million. The Central Subway is also funded by the State of California, the Metropolitan Transportation Commission, the San Francisco County Transportation Authority and the City and County of San Francisco.

Alignment

In February 2008, the San Francisco Municipal Transportation Agency board of directors voted to select the alignment for the subway. In the approved alignment, trains travel north along 4th Street and Stockton Street, stopping at one above-ground station and three subway stations on their 1.7-mile route.
Currently northbound T Third Line trains turn right from 4th Street onto King Street and travel along the Embarcadero to the Market Street Subway. When the Central Subway is complete, trains will instead cross King Street and continue north on 4th Street.
The first stop will be at an above-ground station at 4th and Brannan streets, the 4th and Brannan Station. Heading north, trains will enter the subway through a portal on 4th Street between Bryant and Harrison streets, under Interstate 80. The route will then continue under 4th Street through South of Market, stopping at an underground station, the Yerba Buena/Moscone Station, at 4th and Clementina streets, near the Moscone Center. At Market Street, the subway will dip below the Market Street Subway. Another underground station serving Market Street and Union Square will be located underneath Stockton Street. This combined Union Square/Market Street Station will have entrances at the Market, Ellis and Stockton intersection and within Union Square Plaza at Stockton and Geary streets. A pedestrian passage will connect the Union Square/Market Street Station to the Muni Metro and BART Powell Street Station. The subway will then continue under Stockton Street to Chinatown Station, a station to be located in Chinatown at Stockton and Washington streets. Two of the three underground stations are being constructed using cut-and-cover methods while Chinatown Station is being constructed with the sequential excavation method.
The subway tunnels, one for northbound trains and one for southbound trains, will continue north past Chinatown Station along Stockton Street and terminate near Columbus Avenue. In the future, the northern end of the T Third Line may be extended to terminate in North Beach or to Fisherman's Wharf and the Aquatic Park to connect with F Market & Wharves. Fourteen alternative routes were proposed in a 2014 study to extend the line, and daily ridership was projected to increase by 40,000 if the extension was completed. San Francisco Chronicle architecture critic John King wrote there was "a compelling power to the idea of an extension that, if nothing else, would make the Central Subway seem less like a boondoggle and more of a factor in the shaping of tomorrow’s city. The empty lot of the Pagoda was a starting point for dreams. Let’s see if it can become a starting point of something real as well."

Cost

In 2000, the estimated cost of the Central Subway project was $530 million. By 2001, the cost had risen to $647 million and completion was projected for 2009. When construction began in 2012, the cost had reached $1.6 billion. When the main contract for Central Subway construction was awarded in May 2013 to the lowest bidder, Tutor Perini, the $840 million contract was up to $120 million over the budgeted amount, which took up nearly two-thirds of the entire project's contingency.
Due to the capital cost, the Central Subway project has come under criticism from transit activists for what they consider to be poor cost-effectiveness. In particular, they note that Muni's own estimates show that the project would increase Muni ridership by less than 1% and yet by 2030 would adding $15.2 million a year to Muni's annual operating deficit.
This position is countered by the fact that, unlike new rail construction projections in low-density areas in America, the Central Subway would augment access to the densest portions of Chinatown and the northern Financial District. Current transit access to these areas is provided entirely on the surface through small blocks that feature intense pedestrian activity and narrow streets with multi-modal street congestion. Other, lower-cost rapid transit options were explored, such as bus rapid transit, but were rejected in part because these conditions do not support the basic features of efficient BRT operations.
Compounding these conditions is the fact that many Chinatown residents are transit-dependent and do not own cars, helping rationalize funding for a subway. The high-ridership Muni bus lines serving Chinatown are typically extremely overcrowded, making service for customers more excruciating as excessive boarding activity slows travel speeds or exacerbates overcrowding until no more riders can be accepted and buses are forced to pass customers at successive stops, effectively denying them service.
, Mayor Ed Lee, and other dignitaries next to a poster-sized reproduction of the FTA Grant near Union Square
In October 2012, the Federal Transit Administration announced it would provide $942.2 million for the project under its New Starts program after indicating it would approve the grant in January. This award included the recognition that better, more comfortable service for an already intensively-used transit corridor, particularly for low-income residents as in Chinatown, justifies the investment even if it does not attract a high percentage of "new" riders the way a new rapid transit investment might somewhere that is not already served by extremely slow, uncomfortable high-ridership local service.

Construction

A study released in 2000 called for the Central Subway as part of a larger plan to alleviate projected traffic gridlock which also included a light rail line along Geary. Voters approved the Central Subway in 2003, and the alignment was selected in 2008. Physical work began on the Central Subway in June 2012. The first phases of work included preparation of the tunnel boring machine launch site and headwalls for the Yerba Buena/Moscone Station. At the time, the FTA grant had not been secured, and opponents were threatening lawsuits over potential disruption to traffic and businesses.

Tunnel boring

The two tunnel boring machines are named "Big Alma" and "Mom Chung". Preparations for tunnel boring began on June 12, 2012, with the start of excavation for the TBM launch box on Fourth Street between Bryant and Harrison. "Mom Chung" was delivered to San Francisco in April and May 2013, and in late July 2013, "Mom Chung" began digging the tunnel for southbound T Third Line trains. "Big Alma" began digging north in November 2013 at a slightly faster rate,, compared to the average of "Mom Chung".
The initial plan was to remove the two TBMs near Washington Square in North Beach in 2014 once boring was complete. On July 31, 2012, a lawsuit was filed in Superior Court by Marc Bruno and Save North Beach, a 501 organization of North Beach merchants and residents who believed that the removal of the equipment on Columbus Avenue would cause permanent harm to the neighborhood near Washington Square. The petitioners pointed out in their suit that they are in favor of the City's "Transit First" policy and that they would favor the removal of the equipment if a subway stop was planned, approved and financed for their neighborhood. Muni General Manager Ed Reiskin announced a plan in December 2012 to extend the tunnel to Columbus and Powell, using the site of the long-closed Pagoda Palace theater to extract the TBMs, with a potential option to purchase the Pagoda as the site of a future North Beach station. In 2013, MTA reached a lease agreement with the owners of the Pagoda to tear down the old building and use its site for TBM removal. This will reduce impact of construction on the public space.
On June 11, 2014, "Big Alma" broke through to the North Beach extraction shaft, joining "Mom Chung", which had arrived on June 2. The arrival of the TBMs marked the completion the boring operation phase. The two TBMs were to be disassembled and removed, and the extraction shaft filled in by the end of 2014. The twin tunnels were fully complete by May 2015, when Mayor Ed Lee toured the project underground. Each completed tunnel is long and in diameter, supported by 1,750 concrete rings placed during the boring operation.

Schedule

Just before construction began in 2012, the start of revenue service on the Central Subway extension was scheduled for December 2018. When the main contract was awarded to Tutor Perini in May 2013, schedule float was reduced from 14.8 months to 5.2 months. In 2014, the San Francisco Controller's Office audited the project and predicted it would be completed on schedule in December 2018 and slightly under budget. Tunnel boring completed in June 2014, a month ahead of schedule and under budget.
Over Labor Day weekend 2015, between September 5-8, the track at the intersection of 4th Street and King Street was extended, which temporarily shortened the services of T Third Street between 4th and King Station and Sunnydale Station; the K Ingleside route also ended at Embarcadero Station and did not splice with the T Third Street route. A similar shutdown was imposed in early November 2015. During the November shutdown, bus service was provided in lieu of the T-Third trains between Embarcadero and Sunnydale; E-Embarcadero service was suspended for two weekends; K-Ingleside again terminated at Embarcadero; and streets were closed in the vicinity of 4th and King.
A Project Management Oversight Committee report released in mid-2017 reported ten months of delays in construction, pushing back the date of service as late as December 10, 2019. The $76 million contingency fund may be used to expedite completion. The delays were attributed to work on the Chinatown station. In December 2017, Tutor Perini circulated a report predicting a fifteen-month delay past December 2019 due to circumstances beyond their control, including hard rock and required utility relocations. TPC is liable for penalties of up to $50,000 per day for late completion beyond December 2019.
Also in December 2017, the Central Subway Program Director, John Funghi, announced he will leave the project for Caltrain, where he will head the Peninsula Corridor Electrification Project starting in February 2018. In April 2018, SFMTA announced that excavation was complete for Chinatown station, which will be the last station to be completed for Central Subway in mid-2019. The other underground stations, Yerba Buena/Moscone and Union Square, are scheduled to be completed by the end of 2018 ahead of the scheduled December 2019 start of revenue service.
SFMTA noted that of 37 schedule updates submitted by Tutor Perini between December 2014 and December 2017, 21 were rejected "due to multiple and repetitive issues that vary from incorrect working sequences to unrealistic forecasted completion dates to artificially steering the schedule longest path through certain portions of the project". Contrary to TPC's claims, SFMTA stated that ground conditions were as expected from preliminary surveys, but TPC's "mining productivity has not been as planned" and directed TPC to develop a recovery schedule. In January 2018, for example, TPC modified their construction sequence at Chinatown station and were able to shave 18 days off the schedule, changing the estimated revenue service date to November 22, 2019. By May 2019, the estimated opening had slipped to February 2020. In September 2019, it was announced that the opening was delayed yet again, this time to mid-2021. Another delay to late 2021 was announced in June 2020.

Other issues

Residents and workers near the 4th Street portal and North Beach extraction sites noted an increase in the visible number of rats after construction began.
Construction of the Union Square/Market Street station required closing Stockton Street just north of Market, which depressed traffic to retailers in Union Square. During the excavation, workers accidentally breached a water main in July 2014, causing basement-level flooding in shops along Geary between Stockton and Grant. The ensuing cleanup took several days and required a few businesses to keep stores closed. Since Stockton Street has been closed between Geary and Ellis, starting in 2014, construction is suspended in December and the area is transformed into a pedestrian plaza known as "Winter Walk". Some have called for Winter Walk to be made a permanent year-round fixture, but notable opposition included Rose Pak, who wanted to retain Stockton as a link from Market to Chinatown.
Workers breached a natural gas pipeline in May 2015 while working on the Yerba Buena/Moscone station, forcing the evacuation of the nearby Yerba Buena Center for the Arts.

Art

During construction, murals have been painted on the temporary fences erected around the construction sites. Artworks include:
Permanent installations are planned for each station. Artworks are divided into "landmark" and "wayfinding" categories. Candidates were announced in July 2010 and the winning entrants were announced on August 5, 2010:
A planned installation for 59 bronze sculptures by Tom Otterness at the Moscone station as the wayfinding piece was canceled in November 2011 after it was publicized that Otterness had previously filmed himself in 1977 shooting a dog for the piece "Shot Dog Film".

Fact sheets