82 Miles Per Hour. Thats how fast federal investigators say a commuter train was going when it derailed on sunday. Four people died when the metronorth train jumped the tracks on, on a curve, dozens more were hurt. Investigators now know how fast the train was going. They still dont know for sure why it derailed. Lets take you to jonathan martin. He is at the crash site in the bronx. Jonathan . Reporter hey, tony. You know, investigators have said from the start that this is a very preliminary information, but as you mentioned, these two black box data recorders have revealed key information. One frust from the front and one from the back, showing this train was going too fast echoing what a lot of these passengers and witnesses have been saying from the start. Reporter investigators with the National Transportation safety board say they now know the commuter train that derailed was going too fast as it approached a curve. The preliminary information and let me emphasize this is prelim