VALHALLA, N.Y. (AP) — A packed commuter train slammed into a sport utility vehicle stuck on the tracks and erupted into flames Tuesday night, killing six people, injuring at least a dozen and sending hundreds of passengers scrambling for safety, authorities said.

The northbound Metro-North Railroad train struck a Jeep Cherokee at a crossing in Valhalla, about 20 miles north of New York City, railroad spokesman Aaron Donovan said. Killed were the SUV’s driver and five people aboard the train, he said, making this crash the railroad’s deadliest.

The railroad crossing gates had come down on top of the SUV, which was stopped on the tracks, the spokesman said. The driver got out to look at the rear of the vehicle, then she got back in and drove forward and was struck, he said.

The train shoved the SUV about 10 train car lengths. Smoke poured out of the scorched front rail car, its windows blackened.

Witnesses said they saw the flames shooting from where the crash occurred, in a wooded area near a cemetery.

Ryan Cottrell, assistant director at a nearby rock climbing gym, said he had been looking out a window because of an earlier, unrelated car accident and saw the train hit the car, pushing it along.

“The flames erupted pretty quickly,” he said.

Passengers described a bump and said they smelled gasoline from the vehicle.

More than 750 passengers likely were aboard the train, including Justin Kaback, commuting home to Danbury, Connecticut.

“I was trapped. You know there was people in front of me and behind me, and I was trapped in the middle of a car and it was getting very hot,” he told ABC News. “All the air was turned off so there was no circulation so it was definitely scary especially when people are walking by on the outside and they said, ‘The train’s on fire. There’s a fire.'”

Passenger Stacey Eisner, who was at the rear of the train, told NBC News that she felt the train “jerk” and then a conductor walked through the train explaining what had happened. She said her train car was evacuated about 10 minutes later using ladders to get people out.

The other rail passengers were moved to the rear of the train, which had left Grand Central Terminal in Manhattan about 45 minutes earlier.

Passengers got off from the rear. About 400 of them were taken to the rock climbing gym for shelter. Buses were heading there to pick them up and take them to their destinations.

Metro-North is the nation’s second-busiest railroad, after the Long Island Rail Road. It was formed in 1983 and serves about 280,000 riders a day in New York and Connecticut. Service on its Harlem Line was suspended between Pleasantville and North White Plains after the crash.

Metro-North has been criticized severely for accidents over the last couple of years. Late last year, the National Transportation Safety Board issued rulings on five accidents that occurred in New York and Connecticut in 2013 and 2014, repeatedly finding fault with the railroad while also noting that conditions have improved.

Among the accidents was a Dec. 1, 2013, derailment that killed four people, the railroad’s first passenger fatalities, in the Bronx. The NTSB said the engineer had fallen asleep at the controls because he had a severe, undiagnosed case of sleep apnea.

Last March, the Federal Railroad Administration issued a stinging report on Metro-North, saying the railroad let safety concerns slip while pushing to keep trains on time. Railroad executives pledged to make safety their top priority.