San Francisco Muni completes Central Subway tunneling work

Twin tunnel boring machines have completed their trek beneath two of San Francisco's most congested corridors, completing the tunneling work for the San Francisco Municipal Transportation Agency's Central Subway project.

The tunnel boring machines, which were launched in November 2013, excavated and constructed the 1.5-mile-long tunnels at an average pace of 40 feet per day. During the next several months, the machines will be dismantled and removed from the tunnels to be reused in tunneling efforts in other cities around the world.

Scheduled to open in 2019, the Central Subway is expected to significantly reduce travel times along 4th and Stockton streets, while accommodating the anticipated job and population growth in the South of Market, downtown and Chinatown areas, as well as along the existing T Third Line in eastern and southeastern San Francisco. Three subway stations will be built in the tunnels — Chinatown, Union Square/Market Street and Yerba/Buena/Moscone — while surface-level stations will be built at 4th and Brannan streets.