The Metropolitan Transportation Authority said four or five carriages on the seven-carriages derailed close to the Spuyten Duyvil station in the Bronx, New York.
None of the cars entered the Hudson or Harlem rivers, which are adjacent.
Early reports indicate that four people have died and a further 48 are injured. This figure is expected to change.
More top news
A man who saw his friend die in a lightning strike on the Brecon Beacons described the horrifying moment their adventure ended in tragedy.
A restaurant is facing a backlash after a diner was seemingly sworn at by the company when she posted a complaint on their Facebook page.
Debris found on the island of Reunion has been confirmed by a French prosecutor as being a wing part from missing airliner MH70.