Deep underneath the streets of San Francisco, workers have been busy constructing the Central Subway.
The $1.578 billion project will extend Muni's T-Third metro line, providing a 1.7-mile direct transit link
between the Bayshore/Mission Bay neighborhoods and SoMa, downtown, and
In addition to a street-level station at 4th and Brannan, three subterranean subway stations are currently under construction: the future Yerba Buena/Moscone, Union Square/Market Street, and Chinatown stations.
The Central Subway is expected to open to the public in 2019. But even though that's two years away, here are some photos that capture the project's underground progress: