It was a New Year’s Day to mark a new era for the MTA and residents of the Upper East Side, who had waited decades for the Second Avenue subway line to open.

Cheers went up Sunday at noon among the riders who packed a train as it left the station at 96th Street and Second Avenue on the line’s inaugural downtown ride for the general public.

They were joined by Metropolitan Transportation Authority chairman Tom Prendergast and Gov. Andrew M. Cuomo, who addressed them using the train’s loudspeaker system.

“Let this be one of many successes and a healthy and a happy new year to all of you,” he said. “We deserve it, we need it and I believe we’re going to have it in 2017.”

Long Islanders who take the LIRR and travel through Penn Station to jobs on the Upper East Side are expected to benefit with shorter commutes.

A 40-minute ride from 86th Street to Penn Station will now be reduced to 16 minutes, according to estimates from the Regional Plan Association.

From Penn Station, commuters can take the uptown No. 1, 2 or 3 trains and transfer at the Times Square-42nd Street station to the uptown Q line. They also can walk a block from Penn Station to the Q train stop at the 34th Street-Herald Square station.

Though the new line is expected to save time for commuters, there was a stereotypical snag Sunday on the first downtown trek when the train reached the Lexington-63rd Street station — the stop linking the Second Avenue extension to the rest of the Q line.

Part of Cuomo’s live greeting was garbled by the subway’s loudspeakers.

At one stop it sat for several minutes and a conductor explained over the loudspeaker that it was “experiencing signal problems.”

Riders just laughed. It seemed their mood at the arrival of this historic moment couldn’t be dampened.

Passengers ride the first northbound Q train during the first...

Passengers ride the first northbound Q train during the first day of service to the public on the Second Avenue Subway in Manhattan, Jan. 1, 2017. The first phase, which includes three new stations, at 72nd, 86th and 96th Streets, took nearly 10 years to build and cost $4.5 billion. Credit: Charles Eckert

The train eventually continued on toward Brooklyn.

The Second Avenue subway was conceived nearly a century ago. And though the $4.5 billion first phase delivered only about a quarter of the entire length of the proposed line — 2 miles of 8.5 miles of track — experts and advocates said they anticipate an appreciable impact throughout the subway network.

The prospect of a shorter commute is expected to entice a chunk of riders who currently struggle to pack into trains from the nearby Lexington Avenue line, which serves about 1.3 million riders each day.

Monica Elvira, 40, of the Upper East Side, marveled at the cleaniness of the Second Avenue train and shook a maraca as it headed southward. She wore a “2017” headband. “This is a great way to start the new year,” she said.

In midtown, meanwhile, the first northbound Q train departed from 57th Street-Seventh Avenue station also just after noon.

Passengers ride the first northbound Q train during the first...

Passengers ride the first northbound Q train during the first day of service to the public on the Second Avenue Subway in Manhattan, Jan. 1, 2017. The first phase, which includes three new stations, at 72nd, 86th and 96th Streets, took nearly 10 years to build and cost $4.5 billion. Credit: Charles Eckert

Eager riders gathered hours in advance to ensure they had a seat for the inaugural uptown trip, and hooted and gawked as the train rolled through the three new stations at 72nd, 86th and 96th streets.

“I’m thrilled. This is going to make a huge difference in my life,” said Jaclyn Kelly, 38, who lives near the new 72nd Street stop. “I spent time Googling all the places I can now go to by subway. It’s exciting.”

The cars were filled with plenty of commuters who have taken inaugural subway rides before.

Joe Caronetti, 68, from Norwood, Bronx, said he has been to about five similar events in his lifetime, including the Hudson Yards extension and the opening of the Whitehall South Ferry terminal.

“With all the cutbacks and fare increases, we need this,” Caronetti said, noting that he was disappointed the line wouldn’t travel all the way into his home borough, as originally conceived. “It’s nice to see something given back.”

Charlie Pellet, a radio anchor and voice of the MTA’s announcement system, merrily greeted riders who requested him to repeat commands like “stand clear of the closing doors please.”

He even recorded a new voicemail message for one fan.

The MTA anticipates that the new Upper East Side stations will serve a total of 200,000 riders per day. Commuters nearby will now have a direct connection to several transit hubs, including Times Square, Herald Square and 14th Street.

There will be limited service at the new stations during the first few days to allow for the agency to continue testing elevators and escalators. Trains will run between 6 a.m. and 10 p.m. through next Sunday, before 24-hour service launches.

With Emily Ngo

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