(c) 2013, Bloomberg News.

(c) 2013, Bloomberg News.

ALBANY, N.Y. The deadly derailment on Metro-North Railroad's Hudson Line probably resulted from excessive speed as the train rounded a curve along the Harlem River just north of Manhattan, Gov. Andrew Cuomo, D, said.

"This was a tricky turn on the system, but it's a turn that's been there for decades and trains negotiate it all day long, so it's not about the turn," Cuomo said Monday on NBC television's "Today" show. "I think it's going to turn out to be about speed more than anything and the operator's operation of the train at that time."

The crash Sunday where the Harlem River joins the Hudson caused the first passenger fatalities in Metro-North's 30-year history, the railroad said. Two women and two men died, and 63 were hurt. The train's operator didn't apply the brakes as is normally done when approaching the curve, said a person familiar with the investigation who spoke anonymously because he wasn't authorized to publicly comment.

The engineer, William Rockefeller, was injured and remains in the hospital, according to a person familiar with the accident's details.

Before becoming a locomotive engineer about 15 years ago, Rockefeller, 46, worked in the stationmaster's office as an administrative clerk who posted train schedules in Grand Central Terminal, said Tony Bottalico, general chairman of the Association of Commuter Rail Employees, the union representing Metro-North train operators.

"He has an impeccable work record, he's well-liked by his co-workers and he's trusted," Bottalico said in a telephone interview. "There is nothing that can be construed as accurate as causation at this point. Anything being reported right now is conjecture and it's unfair to everyone involved."

Metro-North's third crash in a year brought new attention to passenger safety on the railroad, which carries an average of 280,000 riders each weekday, second only to the Long Island Rail Road, according to the American Public Transportation Association.

"This is a very important railway for commuters in the New York area," U.S. National Transportation Safety Board member Earl Weener said Sunday at a briefing. "Our mission is to understand not just what happened, but how it happened, with the intent to keep it from happening again."

The NTSB, which is investigating the two other Metro-North accidents this year, will be on site for seven to 10 days, Weener said.

Monday's commute went smoothly even with service suspended between Yonkers and Grand Central. The Metropolitan Transportation Authority, which operates the railroad, provided shuttle buses between Yonkers and the 242nd Street terminus of the 1 subway. Amtrak's Empire Service, whose tracks parallel the Hudson Line, remained in operation.

Peter Macarthur, 43, a commercial banker, took the train from Dobbs Ferry and caught the shuttle from Yonkers to 242nd street, for a 30-minute trip.

"There were tons of buses" in Yonkers, said Peter Macarthur, 43, a commercial banker who took the train from Dobbs Ferry. "It seems well prepared."

The four dead were identified as Donna L. Smith, 54, a paralegal from Newburgh, N.Y.; James G. Lovell, 58, a media consultant from Cold Spring, N.Y.; James M. Ferrari, 59, of Montrose, N.Y.; and Kisook Ahn, 35, of Queens. Three bodies were found outside the train, said Edward Kilduff, chief of the New York fire department. Of the injured, 11 were in serious condition, he said.

Lovell, father of three teenage boys and an adult daughter from a previous marriage, worked for the "Today" show and was married to Philipstown Councilwoman Nancy Montgomery. The town of 10,000 is about 60 miles (97 kilometers) north of New York City along the Hudson River.

"A part of this community has been turned upside down today," Richard Shea, the town supervisor, said in a telephone interview.

Lovell recently survived open heart surgery and cancer, though that didn't deter him from teaching his boys how to high dive at a nearby lake, Shea said. "I remember thinking at the time that the guy was invincible."

Lovell's son, Finn, wrote on his Twitter feed after learning of his father's death, "I wasn't the son of a 'victim.' I was the son of Jim Lovell. I hope to be even half the man he was. I am so blessed and proud of you, Dad."

The NTSB has about 20 investigators assigned to four teams examining signals, mechanical equipment, train workers' actions and the train's interior. The latter team will "try to identify how people were injured or killed," Weener said in an interview at the scene Monday.

The MTA righted the train's locomotive and needs to do the same with the remaining six cars before returning them to the track. Several hundred feet of track must be repaired, said Aaron Donovan, an agency spokesman.

Rescue workers used airbags and other devices to lift train cars to gain access to and search for victims who lay injured or dead underneath the wreckage, said Marjorie Anders, an MTA spokeswoman.

Unlike on an airplane, Metro-North passengers don't have assigned seats, making investigators dependent on witness interviews to determine victims' location and how they incurred injury, said Peter Goelz, a former NTSB managing director, who is now a senior vice president at O'Neill & Associates, a Washington public relations firm.

"You've got to find out where they were and where they ended up; it's just basic detective work," Goelz said.

Two event recorders, known as black boxes, were retrieved from the cab car at the front and the locomotive, which pushed the train from its rear.

The accident could have been prevented through technology called positive-train control, which automatically applies the brake, even when an operator fails to do so, said Ross Capon, president of the National Association of Railroad Passengers, a Washington advocacy group.

"If the brake system was working, it absolutely is PTC- preventable because PTC would've enforced the speed limit," Capon said in an interview.

Railroads face a Dec. 31, 2015, deadline to install the technology to comply with a 2008 law, passed after a Metrolink commuter-rail crash in Los Angeles. Railroads have complained about the cost and sought a delay.

The MTA, the biggest U.S. transit agency, employs 66,000 workers, has a $13 billion budget and carries 8.5 million riders a day on subways, buses and commuter railroads. It's been plagued by deficits for years, which officials have battled with biennial fare and toll increases alongside a cost-cutting plan that began in 2010 and is set to pare more than $1 billion from the operating budget by 2017. Last year, Hurricane Sandy floodwaters caused about $5 billion in damage to its system.

The agency's capital budget provides funding for commuter rail-track maintenance. The five-year, $29 billion budget ending next year includes $1.5 billion for Metro-North, according to budget documents.

In September and October, service on the Metro-North's New Haven line was disrupted almost two weeks when a Consolidated Edison Inc. power failure interrupted service for 130,000 passengers daily in Connecticut and suburban Westchester County in New York. That followed a May 17 collision in Connecticut between trains going in opposite directions. The incident involved 700 passengers, all of whom survived.

Sunday, the southbound express from Poughkeepsie, about 80 miles north of New York City, departed at 5:54 a.m., bound for Grand Central. About 7:20 a.m., the railcars being pushed by a diesel locomotive derailed steps from the Spuyten Duyvil station in the Bronx.

About 120 passengers were aboard, tossed about as several of the red-and-silver cars flipped onto their sides with the lead car coming to rest near the water's edge.

The speed limit on the New York curve is 30 miles per hour, compared with 70 mph before the curve, said MTA spokeswoman Anders. A CSX Corp. freight train hauling garbage derailed there in July.

Sunday, Kelon McFarlane of Poughkeepsie, a 30-year-old telecommunications student at New York City College of Technology en route to visit his aunt in Brooklyn, was in the train's fourth car as it began to make its turn.

"All of a sudden I felt it picked up," and the train leaned over more, McFarlane, 30, said in an interview. "I was thrown from one side to the next."

McFarlane grabbed the overhead rack as the train tipped. The car skidded on its side, pounding and scraping the ground, he said. When it stopped, he and about three other passengers climbed out the exit.

"It was chaotic," he said. "People were screaming."

McFarlane was taken to a hospital to treat cuts and bruises on his hands, upper left thigh and right knee.

_ With assistance from Frederic Tomesco in Montreal, Michelle Kaske, Laura Marcinek, Peter S. Green, Callie Bost and Esme E. Deprez in New York, Michael B. Marois in Sacramento and Angela Greiling Keane in Washington.