Out-of-control subway riders attacked three train operators in less than two hours over the weekend, according to transit and union officials.

One straphanger pushed his way into the cab of a J train, and punched the motorman in the face shortly before 8:30 p.m. at the Essex Street stop in the Lower East Side, officials said. He also hit several other subway riders when they intervened, and then fled.

The train operator was treated at New York Presbyterian Hospital, and no arrests were made, an MTA spokeswoman said.

A boozed-up, unruly rider assaulted a C train motorman with a beer can at the Euclid Avenue station in East New York about 9:25 p.m. He whacked him in the right arm with the can and splashed beer on his uniform.

Another straphanger spat in the face of a northbound G train motorman on the platform of the Court Square station about 10:15 p.m., officials added. He was treated and released from Mount Sinai Hospital.

No arrests were made.

"We're just like sitting ducks," said one of the train operators who was attacked over the weekend and did not want to be identified. "I'm really shocked. There's no respect for authority anymore --  if there was no one there to move the train, how would they get to where they are going?"

The Transport Workers Union Local 100 said there has been  a rash of assaults lately --  with workers spat on, as well as water bottles hurled at them.

"Transit workers lives matter," said vice president Kevin Harrington of TWU Local 100, who called for greater police protection for train crews.

"In two hours late Saturday night, three transit workers were assaulted. All too often, transit employees feel alone, without protection, as they do their jobs in an environment that is often a dumping zone for the mentally ill, a home for street criminals."

He said he would like to see more transit cops riding with conductors and train operators, and protecting station cleaners during late-night shifts.

The MTA said it  was working with the NYPD to track down the assailants and prosecute them.

"An assault on our employees is an attack on all of us," said the MTA in an statement. "These incidents are extremely disturbing and we remain committed to the safety and security of our employees."