You could be standing right on top of the United States' biggest public transportation infrastructure project ever and not have the slightest clue—because its cavernous tunnels are being carved out a full 160 feet below ground.


Known as the East Side Access project, New York's newest railroad will eventually connect the Long Island Railroad to Grand Central Terminal. And the tunnel beneath the East River, which will connect the entire system, was started back in 1969. So that's not even the tricky part.


In a recent interview with Wired, the Metropolitan Transit Authority Capital Construction's crew discussed three of the toughest hurdles that loom before the 2019 due date: the 1,500-foot-long twin caverns that must be carved out beneath Grand Central (while passersby above remain effectively unaware); the process of actually freezing the earth above so traffic overhead wouldn't come toppling down; and "rerouting and fixing cable and wire as they go," so that the trains above don't come to a crashing halt.

Once the project is finished, 160,000 commuters will, supposedly, see much shorter travel times. But until then, the 2,400-odd explosions, countless exposed wires, and monumental concrete formworks make for some incredible footage. You can check out the rest of the images over at Wired. [Wired]