terça-feira, 13 de março de 2012

Uma viagem por baixo de Nova York



Ozier Muhammad/The New York Times
Jimmy Diamond, a sandhog, or tunnel worker, helped the conductor of the Mantrip, a train that carries workers through the tunnel, navigate safely toward Grand Central Terminal.
Some 19 stories under the streets of Manhattan on Thursday, the driver of a 640-ton telescopic tunnel-boring machine stood in a tiny windowless metal cubicle before a pair of small computer screens and an array of buttons and gauges.
“No windshield? Don’t need one,” said the driver (or operator, as he prefers), Anthony Spinoso.
Over several months he has driven the machine 7,700 feet, from a spot deep under Second Avenue and 63rd Street, through the bedrock, to the depths beneath Grand Central Terminal, where the tunnel he has helped dig will someday bring Long Island Rail Road trains to the East Side of Manhattan.
Now he is backing the machine up several hundred feet to a point where it will begin boring a parallel tunnel. Another thing that Mr. Spinoso does not have is a steering wheel. Instead, he guides the movement of the machine with buttons in front of him, striving to hold a green dot (his machine) on the computer screen at the center of a narrow yellow line that represents his programmed course. He must keep the 22-foot-tall, 360-foot-long behemoth on track without varying more than 2 inches in any direction.
“You just push the buttons, it’s like a video game,” said Edward Kennedy, an engineer helping to supervise the work. “The guy has a screen with a yellow line on it, the yellow brick road. All he has to do is keep on the yellow brick road.”
The digging began last fall for the new Long Island Rail Road tunnels — there will ultimately be eight tunnel sections feeding into an immense new station below Grand Central. There are two machines working simultaneously on separate tunnel sections (the second one, which started later, has reached 48th Street). They can cut through 100 feet of rock a day but often move much slower. The tunneling and the excavation of a huge cavern under Grand Central to house the new station are expected to be completed in 2012, but the entire project will not be finished until at least 2015.
The boring is being done for the Metropolitan Transportation Authority by Dragados Judlau, a joint venture of large construction firms. The cost of the tunneling is $428 million, but the entire project, which includes building out the station and laying the tracks, is expected to cost $7.2 billion. The new tunnels will connect to an existing tunnel under the East River and from there (via more tunneling) to Long Island Rail Road tracks in Queens.

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