The Woodside LIRR Station in Queens. View Full Caption mta.info

NEW YORK CITY — Call it the M "Pee" A.

Public urination in the city's transit system isn't just making stations reek — it's actually damaging equipment, Metropolitan Transportation Authority officials revealed this week.

One unfortunate elevator at the Long Island Rail Road's Woodside station in Queens has been inundated with so much urine that its floor has rusted and warped, interfering with its door mechanics and frequently forcing it out of commission.

"The mechanics of the elevator are constantly being contaminated," said LIRR President Helena Williams during an LIRR committee meeting Monday, where she described the lift as having a "vertical urinal problem."

As a result, the elevator, which shuttles riders from the station's mezzanine-level to an LIRR platform, was only in commission 58 percent of the time in February — versus 97 percent for elevators across the LIRR system — making it the worst-performing lift in any LIRR station, an MTA spokesman said.

“The deterioration is significant," he said, adding that maintenance crews weren't sure exactly why the elevator was such a target, considering it was just one of five lifts at the station.

Adding to the mystery is that the station also offers rare public toilets on the mezzanine level.

But the elevators also aren't the only parts of the transit system that have needed to be overhauled because of frequent toilet stops.

Years ago, subway cars had vinyl floor tiles that were laid over plywood. But over time, the plywood floors began to rot and smell foul — which subway officials attributed to urine damage.

In response, New York City Transit switched to "an epoxy floor with marine-grade plywood sub floor," helping to seal out liquids and eliminate the smell.

The agency also switched from aluminum alloy to brass door saddles after it found urine was damaging the devices, which sit under doorways.

The "vertical urinal problem" was mentioned as Williams was updating the LIRR committee on the agency's efforts to bring the system's elevators and escalators into good repair, following the death of an 88-year-old woman on an escalator at the Lindenhurst station last year.

Officials were still working to determine whether the elevator-turned-toilet would need to be replaced or repaired.