Amtrak Crash
Amtrak Crash

President Barack Obama on Thursday thanked first responders and others who helped victims of a passenger train derailment in Philadelphia, and he called for investment in U.S. infrastructure.

Speaking after a summit with leaders of Persian Gulf states at Camp David in Maryland, Obama expressed gratitude for the assistance provided by rescue workers, "who raced to save lives, and for the many passengers who, despite their own injuries, made heroic efforts to get fellow passengers to safety" following Tuesday's derailment.

The president also conveyed his "deepest condolences" to the families of the victims.

Another body was pulled from the wreckage Thursday, pushing the death toll to at least eight, with another 200 injured, some critically.

Obama also stressed the need to invest in the country's infrastructure. "Until we know for certain what caused this tragedy, I just want to reiterate what I have already said — that we are a growing country with a growing economy," he said. "We need to invest in the infrastructure that keeps us that way, and not just when something happens like a bridge collapse or a train derailment, but all the time. That's what great nations do."

Investigators were still trying to determine why the train was traveling at more than twice the posted speed limit before it crashed, but the lawyer for the train's engineer said the man suffered a concussion in the accident and could not recall what happened.

The National Transportation Safety Board said the Amtrak Northeast Regional train was rounding a curve at 170 kilometers an hour.  The posted speed limit is 80 kilometers an hour.

Robert Sumwalt of the NTSB said Thursday that the train accelerated in the last minute or so before the wreck, up from 110 kilometers per hour. He said it was not clear yet whether the speed was increased manually. So far, he said, investigators have found no problems with the track or the signals.

Sumwalt said the engineer, Brandon Bostian of New York, had agreed to be interviewed by the NTSB and that the meeting would take place in the next few days.

Bostian's attorney, Robert Goggin, said the 32-year-old engineer was not on his cellphone at the time of Tuesday's accident, nor had he been using drugs or alcohol.   

"He remembers driving the train, he remembers going to that area generally, has absolutely no recollection of the incident or anything unusual," Goggin told ABC News.

Philadelphia Mayor Michael Nutter told reporters Thursday, "I do not think that any commonsense person would think that it was in any way OK" for the train to be traveling at the speed recorded on the train's black box, which collected key information during the planned trip from Washington to New York.

He said authorities thought they had accounted for all 243 passengers and crew members aboard the train, with 43 still hospitalized with various injuries.

Sumwalt said a new safety feature might have prevented the derailment.  He told reporters that the site where the disaster occurred did not have a system called Positive Train Control, which utilizes GPS and other monitoring devices that automatically slow down a train if it is speeding or in danger of colliding with another train.  

Congress passed a law in 2008 mandating that Amtrak, the government-funded national passenger rail service, and all other private freight and commuter railways install the PTC system by the end of this year.  Amtrak Chief Executive Joseph Boardman said the deadline would be met throughout the northeastern U.S. tracks, including the site of the crash.

Some material for this report came from Reuters and AP.

View full gallery