The MTA is running trains into the gleaming new Long Island Rail Road station beneath Grand Central Terminal – but the public isn’t allowed aboard.

An internal MTA memo obtained by Gothamist shows that on Jan. 11 the LIRR operated 40 empty trains in or out of the station, dubbed Grand Central Madison. MTA officials said the LIRR regularly tests the new service by running trains without riders.

Gerard Bringmann, an MTA board member, said he was told the agency plans to do another “dress rehearsal” of full service on Thursday with no riders aboard. MTA representatives declined to confirm the plan.

The MTA previously planned to open the station by the end of 2022, a deadline set after years of construction delays. The project was originally scheduled to wrap up in 2011.

“I’ll be retired before it happens,” said LIRR rider Kevin Brosnan, 60, after getting off a train at Penn Station.

Brosnan, who lives in Farmingdale and works on the Upper East Side, said the new service could save him an hour of commuting time per workday. “I'll believe it when it’s there, we’ve been hearing this for years,” he said.

The empty service on Jan. 11 was a dry run for what the MTA calls Grand Central Direct, a shuttle with up to two trains an hour between the new Midtown station and Jamaica Terminal. MTA officials announced the service last month as a temporarily truncated version of full service into the new station, which is slated to run up to 24 trains per hour.

But the debut hasn’t happened yet due to a problem with the ventilation system at Grand Central Madison.

The ghost trains are regularly running into the new station while LIRR riders wait for the MTA to fix the problem. The MTA has said the empty trains are used for training workers on the new tracks and terminal.

“Test trains that run sporadically are designed to familiarize staff with new tunnels, signals and related infrastructure,” MTA spokesperson David Steckel wrote in a statement.

Bringmann — who represents LIRR riders on the MTA board — said it’s good that the agency is running safety tests.

"While I'm disappointed with the ventilation issue that's holding up the opening of Grand Central Madison, when it comes to the MTA taking a PR hit versus the safety of our riders, it's a no brainer,” said Bringmann. “Rest assured, the responsible party for this delay, be it the contractor or the mechanical engineer, will be held accountable.”

When full train service to Grand Central Madison opens the MTA plans to boost LIRR train service by 41%.

To prepare, agency officials said the LIRR has hired 207 new workers. There are now 2,500 workers in total trained to operate service into the new terminal — all of whom had to learn how to run trains in the new tunnels and into the new terminal, officials said.

The project — which federal records show costs $11.6 billion, a figure that includes plans to purchase train cars for the service — promises “a new experience” for commuters. But so far the MTA hasn’t said when that experience will be available. While the project has been in the works for more than 20 years, MTA Chairman Janno Lieber last week promised it would be days and weeks, not months, until the service opens.

“It’s a little frustrating, I wish there was an actual opening date,” said LIRR rider Jessica Findlayter, 26, who commutes from Nassau County. She said the new station’s opening would save her two-and-a-half hours a day because her office is next to Grand Central Terminal. The new service would also keep her from paying two subway fares a day to get from Penn Station to Manhattan's East Side.

“I could wake up a little later, maybe make breakfast at home,” she said.

UPDATE: This story was updated with the MTA's reasoning for running empty trains and the project's cost estimate reported by the federal government.