NEW YORK >> A Long Island Rail Road train was traveling more than 10 mph when it crashed at the end of a platform as it pulled into a major transportation hub, injuring 100 people, a federal investigator said.

National Transportation Safety Board investigator Ted Turpin said Thursday the speed limit in the terminal is 5 mph.

The packed, rush-hour train crashed as it entered Atlantic Terminal in Brooklyn on Wednesday morning, hurling passengers onto the floor and slamming them into each other. Many had been standing as they prepared to get off the train at the last stop.

A U.S. official briefed on the investigation and who requested anonymity said the train had been traveling at allowable speeds as it approached the terminal, but in the last three minutes before the crash was speeding up and slowing down between 2 mph and 10 mph.

The official requested anonymity because the official is not authorized to speak about the ongoing investigation.

The train’s 50-year-old engineer told investigators on Thursday he has no memory of the collision, said Turpin. He also told investigators he was not using a cell phone at the time.

“The engineer was unable to recall striking the end of the track,” Turpin said. “He does recall entering into the station and controlling the speed of the train.

Turpin said the man has been an engineer with the LIRR since 2000 and has been working nights for 12 years. He said he’s been on this particular route, which starts shortly after midnight, for the last year and had just come back from three days off.

Results of drug test results are not known yet.

The front of the slow-moving train hit a bumping block as it pulled into the terminal, left the tracks and smashed into a small structure, apparently a work area. A rail pierced the floor of a train car, authorities said.

The bumper “is designed only for very low speed,” Turpin said, adding “there’s nothing that would cushion a train collision” like Wednesday’s.

About 100 people were treated for minor injuries after the 8:30 a.m. crash. The most serious injury appeared to be a broken leg, Democratic Mayor Bill de Blasio said.

The terminal is beneath a shopping mall in downtown Brooklyn, next to the Barclays Center, home to Brooklyn Nets basketball, New York Islanders hockey and major concerts.

A similar accident in nearby Hoboken, New Jersey, in September was much worse. There, a New Jersey Transit commuter train plowed off the end of a track, killing a woman standing in the station. Federal investigators are examining whether a more modern bumper or other barriers could have made a difference.

The train in Wednesday’s wreck originated in the Far Rockaway section of Queens and was carrying around 450 people, officials said.