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First phase of Number 7 subway extension completed

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New York City Mayor Michael R. Bloomberg, Deputy Mayor for Economic Development Robert C. Lieber and Metropolitan Transportation Authority Chairman and CEO Jay H. Walder lauded the completion of the first phase of the Number 7 subway extension at the Hudson Yards in Manhattan. The second of two tunnel boring machines has reached the southern wall of the 34th Street Station cavern after mining a combined 2,900 feet from their starting point at 26th Street under 11th Avenue. The $2.1-billion project, funded by the City and managed by the MTA, will help transform the Hudson Yards vicinity into a vibrant 24-hour neighborhood, containing a mix of commercial, residential, retail, open space and recreational uses.

In January of 2005, the
City Council approved the Bloomberg Administration’s plan for re-zoning the
Hudson Yards area, including the Eastern Rail Yards. The City Council will vote
on the plan for the Western Rail Yards, which would complete the public
approvals process for the development of the area.

"It’s been a half
century since City government expanded its subway system, but that drought will
soon be at an end," said Mayor Bloomberg. "Too often, government
falls victim to the temptation to abandon long-term infrastructure projects
amidst short-term downturns, and that’s why big things never get done. The
redevelopment of the Hudson Yards has been talked about for decades, but with
the expansion of the number 7 line, its potential will finally be
realized."

The tunnel-boring
machines were launched last summer from the underground assembly chamber
located at 26th Street. The first 300 feet of tunneling was complicated by a
section of soft ground between 27th and 28th Streets that required a technique
called "ground freeze" to reinforce the ground, allowing the machines
to pass through as if it were solid rock. As the tunnel boring machines mine,
they place pre-cast concrete lining rings along the excavated tunnel, making up
the permanent liner of the finished tunnel. While the new service will terminate
at the new 34th Street station, the tunnels continue to 25th Street to allow
for the storage of trains.

One tunnel-boring machine
has already started mining north of the station cavern toward 42nd Street while
the other is being pulled through the cavern and will begin mining in a few
weeks. Tunneling north from 34th Street also presents unique challenges, as
track will run under the 8th Avenue Subway, Amtrak/NJ TRANSIT tunnels, tunnels
to the former New York Central Line, the Lincoln Tunnel and the Port Authority
Bus Terminal and ramps. Excavation and underpinning of the 8th Avenue Subway
line is underway to allow the new tunnels to tie into the existing 7 Line tail
tracks at Times Square.

Tunneling will be
completed in the spring of 2010, when work will commence on station entrances
and finishes, as well as support facilities such as ventilation and traction
power substations. The new service will open in December in 2013 as scheduled.

Construction of the
tunnels and the 34th Street Station cavern is being done by S3II Tunnel
Constructors, a joint venture of J.F. Shea Construction, Inc., SKANSKA USA
Civil Northeast, Inc., and Schiavone Construction Co., Inc.

The 7 Line Extension will
introduce subway service to an emerging mixed-use community in Midtown West,
fostering transit oriented development in one of Manhattan’s most underserved
and underdeveloped areas. The City created two local development corporations,
the Hudson Yards Infrastructure Corporation, which is contributing $2.1 billion
to the project, and the Hudson Yards Development Corporation, which oversees
planning and development in the Hudson Yards on behalf of the City.

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