The Metropolitan Transportation Authority says it is ahead of schedule on one leg of its East Side Access project.
Crews completed the third of four tunnels Tuesday that the MTA is building in Queens, seven weeks earlier than planned.
The boring machine that built the tunnel will stay underneath Sunnyside Yard until the tunnel can be connected to the Long Island Rail Road Main Line tracks above it.
It is all part of a plan to link the LIRR to Grand Central Terminal, a project that will affect hundreds of thousands of commuters.
The MTA recently came under fire for the project being behind schedule and over budget.