May 14, 2010 3:08 pm US/Eastern
Boring Manhattan: Ceremony Launches Subway Project
A 450-foot-long "worm" will eat its way through the 470 million-year-old bedrock under Manhattan for the benefit of future subway riders.
The fanciful layman's description of a tunnel-boring machine was provided by geologist and "sandhog" Scott Chesman, who attended a ceremony Friday for the Second Avenue Subway project.
Politicians and other dignitaries descended about 70 feet by stairs, near East 91st Street, as natural light from street level streamed through a big hole. Metropolitan Transportation Authority Chairman Jay H. Walder blew an air horn and switched on the boring machine.
In a couple of weeks, the 485-ton machine will start gnawing through about 50 feet of bedrock per day. The goal is to complete two runs from 92nd Street to 63rd Street by November 2011.
When the machine hits rock, it "makes a real grinding sound," Chesman said. "But it's kind of quiet, compared to drilling and blasting."
The "head" of the borer has dozens of cutters, like "a bunch of teeth," Chesman said. They chip away rock, about 2 inches at a time. The crushed gravel mix, sprayed with a soap-like dust suppressant, is sent down a conveyor belt and loaded onto a work train.
The Second Avenue Subway is expected to be completed by December 2016.
The MTA said the subway eventually will serve more than 200,000 people per day, reducing crowding on the Lexington Avenue line. The neighborhood lost its Second Avenue Elevated in 1940.
The Second Avenue Subway is one of four large-scale transit projects under way in the city, the MTA said in a statement. The agency also is connecting the Long Island Rail Road to Grand Central Terminal, extending the 7 subway line to the west side of Manhattan and building the Fulton Street Transit Center in Lower Manhattan.
"There have been skeptics who saw construction start and stop in the 1970s and said the Second Avenue Subway would never be built," Walder said in the statement. "But today, we are turning on the machine that will dig the Phase 1 Second Avenue Subway tunnels, and we won't turn it off until the tunnels are done."
Chesman, who's seen more than his share of water and subway tunnels, says his fascination with geology doesn't end when he re-emerges, squinting, into the daylight.
When he gets home, he catalogs rocks he keeps in his basement. "My wife doesn't want me collecting any more," he said with a chuckle.
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