The MTA opened a new entrance to the deep-underground Grand Central Madison station Friday, which officials said will give tens of thousands of Long Island Rail Road commuters better access to the transit hub.

The entrance is at 45th Street and Madison Avenue, and gives a new alternative to getting to the station’s platforms, which are 15 stories beneath the street. Commuters can also access the station via Grand Central Terminal and several other entrances and elevators built in nearby skyscrapers.

The MTA announced the work to build the new entrance 18 months ago, and it marks a step forward for the train hub, which opened in 2023 after years of delays and decades of ballooning costs. The MTA has since continued to complete “miscellaneous work” on the station, and most of its retail locations remain empty.

MTA officials celebrated the milestone Friday as a win for convenience and accessibility.

“You just need to stand on Madison Avenue for any amount of time during the morning or afternoon peaks and you can see what commuters want: convenient, accessible entrances that get them to their train without having to go too far out of their way,” Jamie Torres-Springer, the president of MTA construction and development, said at a press conference announcing the new entrance.

MTA Chair Janno Lieber said the entrance was made possible because of a public-private partnership between the agency and BXP, a real estate investment trust that manages offices and workplaces across the country.

As part of the deal, BXP is building a new office tower at 343 Madison Ave., a site that previously housed the MTA's headquarters. BXP said the building is slated to open in 2029 with direct access to the Grand Central Madison concourse. The company announced its anchor tenant, investment firm Starr, earlier this year.

The MTA will get about $1 billion over time through lease payments and taxes because of the deal, Lieber said. He did not specify over what period of time that money will be generated.

“Most important, for today’s purposes, the public, Long Island Rail Road riders, get a brand new, accessible entrance to Grand Central Madison,” Lieber added.

The Midtown station, which brought the LIRR to Manhattan’s East Side for the first time, draws more than 70,000 daily riders, according to the MTA.