Photos: Mayor Lee, public officials, community members celebrate TBM Mom Chung and upcoming start of tunneling
A tour group visits tunnel boring machine Mom Chung beneath busy 4th Street. Tunnel boring machine Mom Chung is almost assembled and just about ready for launch. This month, the 350-foot-long, 750-ton tunnel-building behemoth will begin her journey north beneath the streets of San Francisco, constructing the city’s first new subway tunnel in decades. Last [...]





