If the project stays on track, Long Island Rail Road riders will be able to hop on and off their train at Grand Central by December 2022.

The project is about 60 percent complete, said Michael Horodniceanu, president of the MTA Capital Construction Company, during a tour with reporters 150 feet below the terminal. 

The project, which costs $10.178 billion, is adding eight tracks and a 350,000 square-foot passenger concourse below Grand Central.

Once complete, the MTA says the LIRR access will save thousands of commuters 30-40 minutes of travel time, reduce crowding at Penn Station and provide a quicker route to JFK.

The LIRR will eventually serve an estimated 162,000 riders, according to the MTA. 

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The MTA has already dug the tunnels below Grand Central, and the construction will increase the number of tunnels below the East River to six tracks from four — which the MTA currently shares with Amtrak.  

In Queens, the MTA is working to reconfigure the Harold interlocking, a more than 100-year-old system that sees 780 train movements a day from Amtrak, New Jersey Transit, the LIRR and New York & Atlantic Railway. 

“This is a project of historical proportions that we have never done before,” Horodniceanu said.

Horodniceanu said the MTA is rebuilding and carving out the new tunnels as a way to stay a relevant metropolitan area with excellent transportation access. 

“Like London, like Shanghai, like Paris, you need to have public transport, and it’s important because it provides the additional flexibility to bring people from the East Side of Manhattan to Long Island and vice versa.” 

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“I don’t know, it would depend where I’m working,” said Alyssa Rosello, an LIRR rider waiting for a train at Penn Station on Wednesday afternoon when asked if she would rather hop on at Grand Central. “I guess it would depend on the subway situation also.”

David Alesci, an electrician who rides the LIRR for work all over Manhattan, said he “absolutely” supports the MTA spending money on transit, but doesn’t think Grand Central would help him out. 

“This is a transit hub,” Alesci said of Penn Station. “They should move it [the railroad] to the library where it originally was, because then the 7 train is closer and you can take it over to 42nd Street and there you are. So you don’t have to take a shuttle.” 

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The tunnel tour came a day after elected officials and transportation advocates cried inequity for East Harlem residents in the wake of the MTA slashing the Second Avenue Subway budget to $535 million from $1.5 billion. 

The funding cuts will be for the second phase of the project to extend the Q train up to 125th Street. The first phase, which takes the Q train to 96th Street, is set to open in December 2016. 

Mayor Bill de Blasio also said Tuesday he was “surprised” on the slash in funding in an unrelated press conference, and suggested the cut be reconsidered.  

MTA Chairman Tom Prendergast said in response to the mayor’s statement that the MTA is looking for ways to speed up the Second Avenue Subway project by request of Gov. Andrew Cuomo. 

“We’re 86 years late with the Second Avenue Subway, we have to stop looking in the past constantly and look forward to where we are,” Horodniceanu said of criticism of the progress.