Federal investigators will be looking into why a packed Long Island Rail road commuter train was traveling erratically at twice the speed limit when it crashed at a rail terminal, injuring more than 100 people.

National Transportation Safety Board investigator Ted Turpin said Thursday the train had been traveling at least 10 mph when it train slammed into the end of a platform at Atlantic Terminal in Brooklyn on Wednesday morning; the terminal’s speed limit is 5 mph.

A U.S. official briefed on the investigation said the train had erratically changed speeds in the three minutes before the crash, accelerating and decelerating between 2 and 10 mph.

The official, who was briefed on the investigation but was not authorized to speak publicly about it and spoke on the condition of anonymity, said the train was traveling at allowable speeds as it approached the station.

Federal investigators also will test the train’s engineer for sleep apnea because he exhibited “typical risk factors” for the disorder, the official said, describing the engineer as overweight and adding his wife had complained he snores at night.

The 50-year-old engineer, whose name wasn’t released, told investigators he has no memory of the crash and wasn’t using a cellphone at the time, Turpin said.

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

The engineer was given a drug test, Turpin said, but the results are not yet known.

About 100 people were treated for minor injuries after the crash. The most serious injury appeared to be a broken leg.

(AP)