Digging is done on Central Subway tunnels


San Francisco’s Central Subway project is marking the completion of tunneling of the T-Third rail line subway extension.

The two 350-foot-long tunnel boring machines — known as “Big Alama” and “Mom Chung” — have been creating the two tunnels for the Central Subway since June of last year. “Big Alma” began work in June 2013 followed by “Mom Chung” in November 2013.

The two machines have each tunneled 8,500 feet traveling underneath The City and passing under Fourth Street, Stockton Street and now at the site of the old Pagoda Theater on Columbus Avenue where crews will extract the both machines, according to the San Francisco Municipal Transportation Agency.

The completion of tunneling happened last Wednesday but officials marked the occasion Monday.

The San Francisco Examiner spoke to Central Subway Project Manager John Funghi as “Big Alama” peaked its way through the extraction site:

“It’s like giving birth.”

The Central Subway, The City’s first new subway tunnel in more than 30 years, extends the T-Third rail line to Chinatown at Stockton and Washington streets while making stops underground at Union Square, Fourth and Folsom streets and a surface station at Fourth and Brannan streets.

Director of Transportation Ed Reiskin said in the statement that the milestone highlights how The City is investing and preparing for the future transportation needs for residents:

“As San Francisco grows, it is imperative that we prepare for that growth by providing fast and reliable transit in areas that otherwise face future gridlock and congestion.”

The Central Subway is expected to open to the public in 2019.

Jerold Chinn
Jerold Chinn is the San Francisco Bureau Chief of SFBay. A San Francisco native, he has spent a decade covering transportation in San Francisco. Send tips to or at Twitter @Jerold_Chinn.

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