Yonkers, New York - The National Transportation Safety Board says a train that derailed in New York City was travelling at 132km/h as it approached a 50km/h zone.
The Metro-North Railroad commuter train jumped the tracks on Sunday morning along a sharp curve where the speed limit drops from 70 miles per hour (110km/h) to 30 miles per hour (50km/h). Four passengers died.
National Transportation Safety Board (NTSB) investigators on Monday mined the train's data recorders, shedding light on such things as the train's speed and the use of its brakes. It says it's not aware of any problem with the train's brakes.
The investigators have also sought to question the engineer and conductor for clues. The rail employees union says engineer William Rockefeller was injured in the wreck and is co-operating with investigators.
Four people were killed and 60 others were injured on Sunday morning when the train derailed on a riverside curve in the borough of the Bronx. It was the latest accident in a troubled year for the second-biggest US commuter railroad, which had never experienced a passenger death in an accident in its 31-year history.
About 150 people were on board when the train derailed on Sunday morning on Metro-North's Hudson line.
The NTSB said its investigators could spend up to 10 days probing all aspects of the accident that toppled seven cars and the locomotive.