NEW YORK (AP) — North America's largest commuter rail system is facing a potential shutdown as a deadline nears to reach a deal with unionized workers to avert a strike.

The Long Island Rail Road that serves New York City's eastern suburbs has been negotiating for months on a new contract with labor officials representing locomotive engineers, machinists, signalmen and other train workers.

A strike was temporarily averted in September when President Donald Trump's administration agreed to help. Those efforts ended without a deal, giving both sides 60 days — ending 12:01 a.m. Saturday — to again try to resolve their differences before the union was legally allowed to go on strike or the agency could lock out workers.

Five labor unions representing about half the train system's 7,000-person workforce warned this week that Saturday's deadline was approaching.

READ MORE: Amtrak may make it easier to bring guns on its trains

The LIRR is the busiest commuter railroad in North America, carrying about 250,000 customers each weekday. LIRR workers last went on strike in 1994, for about two days. Workers nearly walked out in 2014 before then-Gov. Andrew Cuomo reached a deal with unions.

The Metropolitan Transportation Authority, which oversees the LIRR and other area transit systems, has said it will provide free but limited shuttle buses during the morning and afternoon rush hours. The agency says the shuttles will depart from designated LIRR train stations to subway stops in the New York City borough of Queens.

Gov. Kathy Hochul has urged LIRR riders to work from home, if possible, as the free shuttles are meant for essential workers and those who cannot telecommute. The Democrat, months earlier, slammed the LIRR unions for "greedy asks" that threaten to "destabilize the local economy."

But there have been signs of progress in negotiations this week.

Months ago, the MTA had proposed to the unions a 9.5% wage increase over three years, in line with what the system's other unionized workers have already agreed to. The unions, however, held out for another yearly salary increase of 6.5%, for a total raise of 16% over four years.

But following Wednesday's closed door meetings, Gary Dellaverson, the MTA's chief negotiator, said the agency offered the unions what it said would effectively amount to a 4.5% raise in the fourth year of the contract. That offer, he said, was in line with what federal officials had recommended and would come in the form of lump sum payments rather than wage increases, as the union sought.

"The difference between those two positions is not unbridgeable," Dellaverson said in a news conference. "It is describable simply in terms of money. There are no longer any complexities involved with the parties."

Kevin Sexton, a spokesperson for the unions, acknowledged Wednesday that there was "positive movement" toward a settlement but dismissed the notion that a deal was close as "far-fetched."

"We would like to reach an agreement that reflects the rising cost of living," he said. "Anything short of that amounts to a cut in real wages."

Spokespersons for MTA didn't immediately respond to emails seeking comment Thursday, but the union said the two sides were expected to continue talks later that night and reconvene Friday if there was still no deal.

Susanne Alberto, a personal trainer from Long Island, said she's already made plans with her Manhattan clients to hold virtual sessions in the event of a shutdown.

She said the union likely has the upper hand, even if she believes raises should be based on job responsibilities and not made across the board.

"The MTA is going to cave, and they know that," Alberto said. "Why don't they just do it now instead of waiting until virtually millions of people get inconvenienced?"

Rob Udle, an electrician who takes the LIRR at least five days a week, said he'll likely use his vacation days rather than navigate the "nightmare" of commuting into Manhattan if the rail service shuts down.

A union member, he sympathized with the unions' affordability concerns, but said he didn't agree with their strongarm tactics.

"I get it, the cost of living is going up and stuff like that," Udle said while waiting at Penn Station for a train home. "But they shouldn't hold everybody hostage to do it. There's a better way. You're affecting a lot of other people."