Metropolitan Transportation Authority And Mayor Bloomberg Preside Over Lowering Of Tunnel Boring Machine For 7 Line Subway Extension
First of Two Machines Will Drill 7,100-Foot Tunnels from 11th Avenue and 25th Street to Times Square
Metropolitan Transportation Authority Executive Director and CEO Elliot G. Sander and Mayor Michael Bloomberg were on hand today as a 100-ton tunnel boring machine (TBM) was lowered under 11th Avenue marking the start of excavation work for the 7 line subway extension project. 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. Sander was also joined by MTA Capital Construction President Dr. Michael Horodniceanu, Congressman Jerrold Nadler, City Council Speaker Christine C. Quinn, Manhattan Borough President Scott Stringer, Deputy Mayor Robert Lieber, and Hudson Yards Development Corporation President Ann Weisbrod.
Governor David Paterson said: "Today we have taken another step forward in updating New York City's aging infrastructure to meet the needs of a twenty-first century metropolis. By extending the Number 7 line to 34th Street and 11th Avenue, we are introducing a vital lifeline to one of our city's least developed areas. As we fight to restore confidence and prosperity in the markets, it is crucial that we promote the economic potential of the new Far West Side."
"As we prepare our next Capital Plan, this project shows that with stable funding in place, we can build monumental works that will serve generations of New Yorkers," said MTA Executive Director Sander. "We are deeply grateful for Mayor Bloomberg's steadfast commitment to this project, and we appreciate and share his understanding of the important role that transportation will play in catalyzing the development of the Far West Side.'
"Today, we're beginning the next and most dramatic phase of the extension of the 7 subway line," said Mayor Bloomberg. "By digging these tunnels, we are expanding our subway network into an entirely new area of the City – Manhattan's Far West Side. It's these major, long-term investments in infrastructure that will transform areas full of promise into neighborhoods full of residents, park-goers, office workers and shoppers."
"We are extremely pleased with the progress and pace of this contract," said MTA Capital Construction President Dr. Michael Horodniceanu. "While this work proceeds, we are looking at packaging the contracts for the follow-on work which includes station entrances and finishes, as well as support facilities such as ventilation and traction power substations."
The piece of the TBM lowered today near the intersection of 25th Street and 11th Avenue, known as the "cutter head," has forty-four rotating discs that will drill a tunnel to Times Square. During the project, two TBMs will excavate two, 7,100 foot-long tunnels.
The 7 line would extend from the intersection of West 41st Street and Eighth Avenue, west under 41st Street, and turn south under 11th Avenue. A new terminal station would be located at 34th Street and 11th Avenue, allowing convenient access to the adjacent development, and Convention Center. Additional storage tracks would be provided beyond the terminal station, and the subway structure would terminate at the site of today's event. Modification to the MTA's Corona Yard would be required to help provide storage for the additional trains necessitated by the extension of the 7 line.
The TBMs were tested by the manufacturer, Herrenknecht AG at its workshop in Schwanau, Germany last November and then disassembled for delivery in three separate shipments by boat. The first shipment arrived in early January, the second in early February and the third is scheduled to arrive later this month. Once on site, the individual components of the machines will be lowered into the launch chamber where they will be assembled. The 22-foot diameter cutter head lowered today, consisting of three components, was bolted and welded at the site prior to being lowered into the chamber.
It will take approximately two months to assemble each machine, with the first one scheduled to begin excavating toward the end of April. The second TBM will launch approximately one month later, in mid-May. The excavation will run under the 8th Avenue Subway Line, Amtrak/NJT tunnels to the west, Amtrak tunnels to the former New York Central Line going north, the Port Authority Lincoln Tunnels and the Port Authority Bus Terminal and ramps. Both TBMs are scheduled to finish the required excavation in the Spring of 2010, at which time the follow-on work will begin, with the new service opening in December 2013.
Each TBM will place pre-cast concrete lining rings, 1,890 in total, along the tunnel as it excavates. The lining rings make up the permanent liner of the finished tunnel. In addition, the crushed rock, a by-product of the excavation known as muck, will be carried via a conveyor belt system from the cutter head to the back of the TBM where it will be loaded onto muck cars. The cars will transport the muck back to the launch shaft, using a temporary rail system installed in the tunnels, where another conveyor belt will carry it to the surface.
While work progressed in creating the TBM assembly chamber, the station cavern underneath 34th Street and 11th Avenue was also being mined using controlled drill-and-blast. Station cavern excavation continues and will be completed by September 2009 in time for the TBMs to reach the mined cavern where they will be "walked" through to begin the next leg of their excavation journey.
"It's quite a milestone to be able to witness – literally, through steel blades and concrete – the progress of this major project," said Congressman Nadler. "This tunnel boring machine represents jobs and major infrastructure development for New York City, something we could definitely use a lot more of."
"Part of confronting the economic crisis on the local level is to make sure that we continue to build the critically important infrastructure projects in the face of these challenges. Continuing the construction of the 7 line is one of those projects because it will allow development to get started as soon as the economy turns the corner," said Speaker Quinn. "The 7 Line will not only open up the Hudson Yards and get us moving on the road to recovery—it will open up one of the last great frontiers on the island of Manhattan."
In December 2007, a $1.14 billion contract was awarded to S3II Tunnel Constructors –a joint venture of J.F. Shea Construction, Inc., SKANSKA USA Civil Northeast, Inc., and Schiavone Construction Co., Inc. – to construct the running tunnels and station cavern at 34th Street.
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 (HYIC), which is contributing $2.1 billion to the project, and the Hudson Yards Development Corporation (HYDC), which oversees planning and development in the Hudson Yards on behalf of the City. In January of 2005, the City Council approved the Bloomberg Administration's plan for re-zoning the Hudson Yards area.