Some 130 feet below Grand Central Terminal, massive drills and backhoes tear away at 500 million-year-old rockbed, carving out a space that will rival its upstairs neighbor in size when it's finished.
At distances of 40-100 feet of rock every 24 hours, it is a labor-intensive undertaking measured in years, not days. When completed in September 2019, it will give more than 160,000 Long Island Rail Road passengers access to Grand Central every day.
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But as the work of the East Side Access project approaches the halfway mark toward completion, something resembling the finished product is beginning to take shape.
Massive subterranean caverns have been blasted and dug. Six miles of tunnels have been created in Manhattan alone.
On Tuesday, a belowground tour traversing some 4 miles of the streets below Grand Central revealed tunnels that were mud-splattered and roughly dug.
Soon, they will be transformed into four state-of-the-art platforms and eight tracks, situated beneath a gleaming, 350-square-foot concourse -- the largest terminal built in the U.S. since the 1930s.
"What you see here right now is the start of the next 100 years for Grand Central," said Michael Horodniceanu, the Metropolitan Transportation Authority's president for capital construction.
Decked out in an orange vest and hardhat, the avuncular Horodniceanu led the media on a tour Tuesday of the current state of the $8.24 billion project.
Horodniceanu is an unabashed booster for the project who sold a successful business for a chance at putting an exclamation mark on his 40-year career as an engineer.
"If you're an engineer, this is a dream come true," Horodniceanu said, a smile creasing his bearded face. "When it was offered, I said, 'OK, show me where I sign.' You can't refuse it. It's a legacy that you can think of leaving behind ... We expect to have a station and a concourse that will be worthy of Grand Central."
The difference, Horodniceanu said, is that Grand Central was built aboveground while the East Side Access project has required workers to create a new terminal below the existing Metro-North tracks without destabilizing what's above.
"We're building it underground," he said. "It's a totally different paradigm."
Structures above must be girded and stabilized before blasting takes place, he said.
"You need to do it in such a way that nothing moves," Horodniceanu said. "People do not see the amount of work that goes into creating this thing. It's an incredible thing."
All together, 23.5 million cubic feet of dirt already has been removed -- enough to cover Central Park in a foot of dirt.
And yet, Horodniceanu said, the sound of blasting and drilling of rock has barely registered with Grand Central commuters rushing off to catch trains above.
"We're able to do it in a stealth fashion," Horodniceanu said before alluding to another of his projects, which has played out in full view to the dismay of Manhattan's East Side residents.
"Unlike Second Avenue, that stealth eluded me totally," Horodniceanu noted wryly. "Here, we are able to do it without disturbing the peace and quiet of the people who enjoy Grand Central."
In the years to come, tunnels will be outfitted with signals, switches and ventilation ducts. Dozens of escalators will be installed to ferry LIRR passengers up into the terminal or out onto the streets above.
But, Horodniceanu said, he has been through enough of such megaprojects to know that the endgame is often harder than the groundbreaking.
"I would never minimize the finishes," Horodniceanu said. "It's easier to do the rough job."
Most of the tunnels will be completed by June, and some 75 percent of the contracts will be awarded by the end of the year, Horodniceanu said.
"After that, we're going to build, build, build," he said.
Inevitable hurdles and unforeseen obstacles will arise before the terminal opens to passengers, the engineer said. "And I hope to be there when it's done," he said.
"If you can do something that was never done and you're successful in doing it," he said, "this is great."