The Long Island Rail Road’s first new train cars in nearly two decades rolled out during the Wednesday morning rush hour.

The eight-car M9 train made its debut shortly before 7 a.m., going from Huntington to Hunterspoint Avenue. The train will have other runs throughout the day, on the Hempstead and Babylon lines.

In the coming weeks and months, the railroad will roll out additional cars, until all 202 are added to the fleet, likely by March 2021.

"We're proud to be putting it into passenger service. Our customers have been very patient, and we appreciate that," LIRR president Phillip Eng said while onboard the train during a preview run Tuesday. "This is exactly what they've been telling us they need: a reliable fleet, a clean fleet."

The cars represent the first significant addition to the railroad’s fleet since 2002, when the LIRR introduced the M7 electric cars that now make up the majority of the agency’s trains. The trains are expected to eventually replace many of the railroad's antiquated M3 cars, which are nearly 40 years old and make up about 12 percent of the LIRR's fleet.

The M9 cars look similar to the M7 cars, with navy and gray walls and blue vinyl seats. But the "state-of-the-art" cars, as Eng called them, include several new amenities, including electrical outlets at every row of seats, automatic pocket doors in between train cars that open with the press of a button, and digital displays that tell riders which car they’re in (e.g.: “Car 2 of 6”). Another digital display on the exterior of the front car of the train will tell passengers waiting on platforms the train's destination.

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Other features include "no-touch” hand dryers, toilets, soap dispensers and faucets in bathrooms; increased window tint to reduce sun glare; four 32-inch multimedia screens showing ads and service information in each car, and closed-loop seat armrests that are less likely to snag and rip clothes than on the M7 trains. The seats — 217 between every pair — are slightly wider than on previous cars.

The rollout follows years of delays and frustrations for LIRR officials — and riders. In September 2013, the railroad awarded a contract to Kawasaki Rail Car Inc. to design and manufacture the cars, which are needed to replace the railroad’s oldest cars and address surging ridership, which is expected to grow more once the railroad links to Grand Central Terminal in 2022. The total cost of the M9 purchase is $550 million, according to the LIRR.

The first cars were supposed to begin rolling out in September 2017, but manufacturing was besieged by setbacks, including design problems and a derailment last year of several of the cars before they could be delivered. The LIRR had expected to debut the trains in May, but Eng said new issues arose in testing. In July, Kawasaki officials said they expected them to be ready by the end of August.

#LIRR The first new train in 17yrs the M9, heading to hunters point Queens. pic.twitter.com/xm0U8jyOqn — Marvin Hoffman (@theeye74) Sep 254, 2019

Eng said Tuesday that the recent delays were due to "rigorous testing" that the cars underwent. The LIRR requires every car to log 4,000 miles of test runs before being put into service.

"The worst thing we could have done was to put them into service when they weren't ready, only to have to pull them out of service," Eng said.

The arrival was celebrated by rider advocates, including LIRR Commuter Council chairman Mark Epstein, who said the trains "are sorely needed and long overdue."

"We fervently hope the rollout is successful and that a full contingent of new cars will soon follow," Epstein said.

State Sen. James Gaughran (D-Northport) said the rollout follows "two years of setbacks and delays, which have led to mounting customer frustration."

"To say this is a long time coming is an understatement," Gaughran said.

State Sen. Todd Kaminsky (D-Long Beach) said the new cars will help deliver the "sane and dignified commute" LIRR riders crave.

"Having additional, newer cars will mean less-crowded and more comfortable commutes, something LIRR riders have long deserved," Kaminsky said.