After a dozen years that included a successful tunneling feat and an unusual arrangement for station work, a 1.7-mile, $1.9-billion extension of San Francisco’s Central Subway wrapped up this month.
The San Francisco Municipal Transportation Agency (SFMTA) began planning for the overall system in the late 1980s to provide more transit on 3rd Street and in Chinatown. After six years of construction, the first 5-mile phase, called the Third Street Light Rail Project, opened in 2007. In 2013, work began to add the Central Subway’s 1.7 miles, with new stations in SoMa, Union Square and Chinatown. Tunnels over a mile long run as deep as 120 ft under the streets.