The driver whose speeding commuter train derailed along a curve, killing four people, nodded off at the controls before the crash, it has emerged.

A commuter train that derailed in New York, killing four passengers, was travelling at 82mph as it entered a 30mph curve, a US government investigator has said.

A train that derailed in New York City, killing four people and injuring dozens more, was travelling at 82mph as it approached a 30mph zone, officials have disclosed.