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Tunnel Boring Machine Finds Final Resting Place

<p>Its work complete, one of two 200-ton, 22-foot-tall tunnel boring machines digging the tunnels and caverns that will bring Long Island Rail Road trains into Grand Central Terminal is being buried this week, 14 stories below Park Avenue.</p>
<p>Of course, it's already been underground since 2007 when it began digging the tunnels. But now it's being "buried," or permanently sealed behind a wall at the end of the last tunnel it built and encased in concrete. Believe it or not, it is actually saves money to bury the machine at the end of the tunnel rather than try to retrieve the spent monster from the far end of the tunnel or sell it for scrap.</p>
<p>The machine -; even the super-strong tungsten carbide cutters that make up its face -; takes a serious beating during the process of digging a tunnel through Manhattan bedrock. There aren't many buyers for a used, beaten-up tunnel boring machine. But sometimes a machine can be sold for scrap metal. In this case, though, MTA Capital Construction's contractor, Dragados, the owner of the machine, would first have to cut it to pieces using blowtorches, then laboriously extricate each piece and transport them through the two-mile tunnel to Sunnyside, Queens, blocking the movement of construction equipment and personnel and causing costly delays to the progress of the project. And, in order to keep the tail end of the tunnel structurally sound if the machine were to be removed, workers would have to build a concrete lining on the last few feet of the tunnel where the machine had been. (In most parts of the tunnel, the tunnel boring machine itself creates the concrete lining as it travels. But it can't do it until it's moved all the way through an area.)</p>
<p>So to prevent these added costs and to keep the tail end of the tunnel structurally sound, workers are sealing the tunnel boring machine in behind a bulkhead and encasing it in concrete to prevent it from oxidizing and decaying over decades. So by supporting the end of the tunnel, the tunnel boring machine in a way will continue to serve a purpose into perpetuity.</p>
<p>The East Side Access project, the nation's largest transportation project, is building a direct connection between the Long Island Rail Road and Grand Central Terminal. It will directly serve about 160,000 customers a day while nearly doubling LIRR train capacity into Manhattan and freeing up seating space throughout the railroad.</p>
<div style="width:600px; margin:0 auto; text-align:center;"><img src="/sites/default/files/archive/imgs/tbm.jpg" alt="Tunnel Boring Machine Photo"><br />
<span class="caption">This tunnel boring machine, part of the East Side Access project, is being encased in concrete this week. It is shown here after completing an earlier tunnel underneath Grand Central Terminal. Photo by Metropolitan Transportation Authority / Patrick Cashin.</span></div>