Emergency workers walk past a derailed Metro-North train in New York, in this still image from video taken by the National Transportation Safety Board (NTSB).
The driver of a New York commuter rail train that derailed on Sunday, killing four people, told investigators that he "lost focus" shortly before the crash, according to a law enforcement source.
Investigators said on Monday he took the seven-car Metro-North train into a curve at almost three times the posted speed limit. The driver, who is still being questioned by the National Transportation Safety Board, told investigators that he realized too late that his speed was too great and hit the brakes without enough time to bring the train under control before the curve, the source said.
© Thomson Reuters 2013