This week we'll be welcoming Mom Chung, one of the two tunnel boring machines that will excavate and construct the Central Subway tunnels. Crews will assemble the 300-foot-long machine in an excavation beneath 4th Street before she begins her journey north.
The two massive machines will take four to six weeks to assemble once they arrive from China. Once built, the machines will be dropped into a launch box below Fourth Street, where they will start drilling at about 40 feet per day.
Crews of six to nine people will man the massive machines, which will dig as deep as 150 feet below the surface. The machines are expected to reach their extraction site in North Beach next April, about 10 months after the start of work.
So who's going to get me a tour?