On Sept. 20, sandhogs working on the New York Metropolitan Transportation Authority’s East Side Access megaproject broke through the final piece of reinforced concrete separating newly built tunnels in Queens from newly built tunnels in Manhattan. In so doing, they created a continuous tunnel running more than three and a half miles from a cavern 12 stories underneath Grand Central Terminal to four concrete-lined, 22-foot-diameter tunnels just feet below the Sunnyside rail yard in Queens that will soon be connected to the Long Island Rail Road (LIRR) main line.

“For the first time since the East Side Access project began, there is now a continuous path through newly built tunnel from Queens to the east side of Manhattan,” said MTA Chairman and CEO Joseph J. Lhota. “This is the path Long Island Rail Road trains will follow when this project is completed.”

This segment of tunnel is unique in that it supports the weight of both a six-lane highway and two MTA New York City Transit subway lines, one underground and one elevated. Project workers drove a new set of foundation pilings into the ground to temporarily support the Astoria Line tracks and their elevated structure during construction, then shifted the track from its permanent foundation supports to the temporary site. The permanent foundation had protruded into the right-of-way where the new tunnel is being built and is being modified to rest on top of the newly completed section of LIRR tunnel.

“This is the most complicated and challenging 120 feet of tunnel we’ve built on any of our construction megaprojects,” said Dr. Michael Horodniceanu, president of MTA Capital Construction, the agency building the East Side Access project. “That it is being completed as intended is a testament to human ingenuity and perseverance.”

Because the ground is soft at this site and difficult to control during excavation, it has been frozen to allow for increased control and rigidity.

Photo by Metropolitan Transportation Authority/Nichole Guernsey Sandhogs working on New York MTA’s East Side Access project break through the last piece of wall separating the new Manhattan and Queens tunnels. The contiguous tunnel is more than three and a half miles long, from Sunnyside Yard in Queens to 37th Street and Park Avenue in Manhattan. The work took place in the tunnel drift at left.