NEW YORK - US experts on Monday began to probe how and why a New York City commuter train derailed over the holiday weekend, killing four, injuring more than 60, and nearly plunging into a freezing river.
The train may have been speeding when it veered off the rails in the Bronx borough at around 7:20 am (1220 GMT) Sunday as it headed south to Grand Central Station in Manhattan.
The New York Fire Department said four people were killed, 11 others seriously injured, and another 56 suffered minor wounds.
Some passengers were "impaled" by debris as train cars flew into the air, officials said, while others had to be cut free from tangled metal.
"People were screaming," Joel Zaritsky told The New York Times. "I found myself thrown to the other side of the train."
Many survivors had broken limbs or injuries to their heads or necks. Some were led away with bloodied faces.
Investigators combed the scene and announced that a "multi-disciplinary team" would probe everything from the condition of the tracks to the signaling systems and the brakes.
"Our mission is to understand not just what happened, but why it happened, with the intent of preventing it from happening again," Earl Weener, a National Transportation Safety Board official, told reporters.
Weener said the train's event recorder - similar to an airplane's "black box" - had been recovered.
The data "will say how fast the train was traveling and whether or not the brakes were applied," New York Governor Andrew Cuomo said in earlier remarks to broadcaster MSNBC.