A new report says the engineer in the Metro-North train derailment in the Bronx that killed four people had a record of speeding.

The National Transportation Safety Board report says data collectors have shown that William Rockefeller sped in four out of six runs the week before the Dec. 1 crash.

While the cause of the derailment remains under investigation, the NTSB has said Rockefeller suffered from sleep apnea and felt dazed before the train jumped the track.

The MTA released a statement about the new data, saying in part, "The overspeed events noted in the NTSB data released today all occurred prior to the Dec. 1 derailment. The analysis was done a month after the derailment in January 2014."

The cause of the crash is still under investigation. Since the derailment, Metro-North has implemented an aggressive speed compliance program, including more random downloads, more radar checks and more on-board supervision.