This is not the kind of mass-transit relief New Yorkers had in mind.

Straphangers aboard Queens-bound N and Q trains are tired of having their subway turned into the “P line” by a motorman who’s tossing juice bottles filled with urine out his window at the Astoria Boulevard station, The Post has learned.

Three motormen who regularly man the hour-and-15-minutes route — which stretches from Stillwell Avenue in Brooklyn to Ditmars Boulevard in Astoria — say the pee problem has been an ongoing issue.

“It’s disgusting,” one train operator said. “It’s been going on for at least five years.”

The urine-filled Tropicana, Poland Spring and Crystal Geyser jugs line up directly with where the motorman’s window stops at the station, and are sprinkled across the elevated platform’s awning overlooking the Neptune Diner below.

And last week, The Post witnessed an N-train operator dumping out a bottle filled with a mysterious liquid in the same spot as the stream of bottles.

“Everyone knows it’s going on,” another motorman said. “There are notices from higher-ups saying not to do it. They say, ‘We tell our customers not to litter, so don’t litter.’ ”

Riders were nauseated to learn that the bottles, which have sat untouched for at least a month, were filled with something other than lemonade.

“That’s not where urine is supposed to go,” said Chris Grioli, a 28-year-old Astoria resident. “It’s supposed to go in the toilet.”

Other commuters were worried that the waste could fall from the awning, splattering all over the street.

“It could hit a car or a pedestrian,” said Antun Grancaric, 25. “It’s disgusting and not a good image for the MTA.”

An MTA spokesman said the bottles would be removed “as soon as possible” after The Post alerted them to the pee proliferation on Sunday.

“This conduct is inappropriate but we will refrain from commenting further until we investigate further,” Kevin Ortiz said.

Train operators normally get a 15-minute break at the end of their run — and if nature calls during their route, Ortiz said they can call the Rail Control Center to take a “comfort break.”

Both the Astoria Boulevard and Ditmars Boulevard stations have working bathrooms for employees to use, and there is a garbage can less than 10 feet from the motorman’s door at the last stop.

An MTA rulebook “strictly prohibits” littering on any subway property, specifically stating that employees “must deposit ALL refuse in waste receptacles provided for this purpose.”