NEW YORK -- A New York City commuter train rounding a riverside curve derailed Sunday, killing four people and injuring more than 60 in a crash that threw some riders from toppling cars and swiftly raised questions about whether excessive speed, mechanical problems or human error could have played a role.
Some of the roughly 150 passengers on the early morning Metro-North train from Poughkeepsie to Manhattan were jolted from sleep around 7:20 a.m. to screams and the frightening sensation of their compartment rolling over on a bend in the borough of the Bronx where the Hudson and Harlem rivers meet across from the northern tip of Manhattan. When the motion stopped, all seven cars and the locomotive had lurched off the rails, and the lead car was only inches from the water. It was the latest accident in a troubled year for the nation's second-biggest commuter railroad, which had never experienced passenger death in an accident in its 31-year history.
Sunday's accident came six months after an eastbound train derailed in Bridgeport, Conn., and was struck by a westbound train. The crash injured 73 passengers, two engineers and a conductor. In July, a freight train full of garbage derailed on the same Metro-North line near the site of Sunday's wreckage.
Joel Zaritsky was dozing Sunday as he traveled to a dental convention aboard the train. He woke up to feel his car overturning several times.
"Then I saw the gravel coming at me, and I heard people screaming," he said, holding his bloody right hand. "There was smoke everywhere and debris. People were thrown to the other side of the train."
In their efforts to find passengers, rescuers searched nearby woods and waters and used pneumatic jacks and air bags to peer under wreckage. Crews planned to bring in cranes during the night to right the overturned cars on the slight chance anyone might still be underneath, said Earl Weener, a National Transportation Safety Board member.
The agency was just beginning its search into what caused the derailment, and Mr. Weener said investigators had not yet spoken to the train conductor, who was among the injured.
Meanwhile, thousands of people braced for a complicated morning commute today, with shuttle buses ferrying passengers to another line.
Investigators were due to examine factors ranging from the track condition to the crew's performance. Gov. Andrew Cuomo said the track did not appear to be faulty, leaving speed as a possible culprit for the crash. The speed limit on the curve is 30 mph, compared with 70 mph in the area approaching it, Mr. Weener said.
Authorities did not yet know how fast the train was traveling but had found a data recorder, he said.
One passenger, Frank Tatulli, told WABC-TV that the train appeared to be going "a lot faster" than usual as it approached the sharp curve near the Spuyten Duyvil station.
Nearby residents awoke to a building-shaking boom.
Within minutes, dozens of emergency crews arrived and carried passengers away on stretchers, some wearing neck braces. Others, bloodied and scratched, held ice packs to their heads.
The MTA identified the victims Sunday as Donna L. Smith, 54, of Newburgh; James G. Lovell, 58, of Cold Spring; James M. Ferrari, 59, of Montrose; and Ahn Kisook, 35, of Queens.
Three of the dead were found outside the train, and one was found inside, authorities said. Autopsies were scheduled for today, the New York City medical examiner's office said.
Eleven of the injured were believed to be critically hurt and another six seriously hurt, according to the Fire Department. After visiting an area hospital Sunday evening, New York City Mayor Michael Bloomberg told reporters that the 11 who originally were critical no longer appear to have life-threatening injuries.
To Mr. Cuomo, the scene "looked like a toy train set that was mangled by some superpowerful force," the governor said in a phone interview with CNN.
As deadly as the derailment was, the toll could have been far greater had it happened on a weekday, or had the lead car plunged into the water instead of nearing it. The train was about half-full at the time of the crash, rail officials said.
The affected line, called the Hudson line, carries about 18,000 people on an average weekday morning.
For decades, the NTSB has been urging railroads to install technology that can stop derailing caused by excessive speed, along with other problems.
A rail-safety law passed by Congress in 2008 gave commuter and freight railroads until the end of 2015 to install the systems, known as positive train control. Aimed at preventing human error -- the cause of about 40 percent of train accidents -- it can also prevent trains from colliding, entering tracks undergoing maintenance or going the wrong way because of a switching mistake.
But the systems are expensive and complicated. Railroads are trying to push back the installation deadline another five to seven years.
Metro-North is in the process of installing the technology. It now has what's called an "automatic train control" signal system, which automatically applies the brakes if an engineer fails to respond to an alert that indicates the speed is excessive.
Such systems can slow trains in some circumstances but not bring them to a halt, said Grady Cothen, a former Federal Railroad Administration safety official.