NEW YORK (AP) -- Federal investigators say they're trying to determine whether excessive speed, mechanical problems or human error could have played a role.in the deadly derailment of a commuter train in New York City.
The National Transportation Safety Board says it will be examining the train's data recorders to find out what happened.
The Metro-North train came off the tracks Sunday morning as it was rounding a riverside curve in the Bronx, killing four people and injuring more than 60.
The Metropolitan Transportation Authority says two men and two women died.
Crews plan to bring in cranes during the night to right the overturned cars on the slight chance anyone might still be underneath.
The NTSB says investigators have not yet spoken to the train conductor, who was among the injured.
Meanwhile, thousands of people are bracing for a complicated Monday morning commute, with shuttle buses ferrying passengers to another line.
Officials say the accident is the second passenger train derailment in six months for Metro-North, and the first passenger death in an accident in its nearly 31-year history.
Meanwhile, Amtrak, whose trains run along the same rail line, has restored service between New York City and Albany, N.Y., but it says delays can be expected.
MTA identifies 4 people killed in NYC train crash
The Metropolitan Transit Authority has identified the four people killed after a New York City commuter train derailed.
The MTA identified the victims Sunday as 54-year-old Donna L. Smith of Newburgh; 58-year-old James G. Lovell of Cold Spring; 59-year-old James M. Ferrari of Montrose; and 35-year-old Ahn Kisook of Queens.
Family members for Smith and Lovell didn't return messages seeking comment Sunday. Relatives for Ferrari and Kisook couldn't immediately be reached.
More than 60 others suffered injuries in the early morning crash.