NOTE: Anyone who was a passenger on the train, even if they are unhurt, should call the Amtrak Hotline at 1-800-523-9101.
Seven people are dead in an Amtrak train derailment that injured dozens and plunged screaming passengers into darkness and chaos Tuesday night.
Amtrak Train 188 was traveling at 106 mph as it raced into a sharp curve in the tracks in Philadelphia's Port Richmond section shortly after 9 p.m. Tuesday, the National Transportation Safety Board confirmed.
The engineer, identified by NBC News as Brandon Bostian, applied full emergency brakes, but all seven passenger cars and the locomotive derailed, said NTSB spokesman Robert Sumwalt. The train was still traveling at 102 mph when information from the data recorder terminated.
The maximum speed at the curve was 50 mph.
The train, a Northeast Regional, was en route from Washington to New York with 238 passengers and five crew members aboard.
A Naval Academy midshipman, an Associated Press staff member, a tech company CEO and a Wells Fargo senior vice president were among those killed. More than 200 people went to hospitals to be evaluated or treated for injuries.
The bodies of four victims were found inside the train; two were found outside, a Philadelphia police spokesman said. Another victim died at an area hospital.
Philadelphia Mayor Michael Nutter confirmed five deaths Tuesday night. Temple University Hospital said early Wednesday that another person died there overnight from a chest injury; that person was later identified as the Associated Press employee.
The police spokesman confirmed a seventh death early Wednesday afternoon.
Some people remained unaccounted for, raising fears the death toll could rise, but Nutter said some of them may simply have not checked in with officials or may have taken a different train.
"We have not completely matched the manifest" from Amtrak with patient or hospital records, he said, calling it a tedious process.
Nutter said Wednesday afternoon that the search continued for any additional victims.
"We will not cease our efforts until we are absolutely sure that we have gone through every [train car]," he said Wednesday afternoon. The search area has been expanded in case anyone was thrown from the train, he said.
Sam Phillips, director of Emergency Management for Philadelphia, said Wednesday afternoon that officials have made "good progress" in reconciling several collections of data. She asked that any passengers who walked off the crash site Tuesday night call Amtrak's hotline at 1-800-523-9101.
Nutter said he spoke to D.C. Mayor Muriel Bowser Tuesday night about the possibility of D.C. residents being on the train.
"We are heartbroken at what has happened here," he said, adding that nothing like this has happened "in modern times."
Bowser said Wednesday that D.C. residents were on board the train, but she was not able to say how many.
Federal investigators from the NTSB began arriving between 4 and 5 a.m. Wednesday to begin examining the twisted wreckage and determine what went wrong.
"I've Never Seen Anything So Devastating"
Witnesses said the scene of the derailment was horrific, with cars "completely overturned, on their side, ripped apart," Nutter said Tuesday night. One car came to rest perpendicular to the tracks, officials said.
Chopper video from the scene showed train tracks twisted underneath the cars. Passengers could be seen fighting their way out of the cars and milling in groups near the train.
"It is an absolute, disastrous mess," Nutter said.
Rescuers struggled overnight Tuesday to determine how many casualties there were in the wreckage. Officials stressed the final number of casualties was preliminary and may change.
"I've never seen anything so devastating," said Philadelphia Fire Department Deputy Commissioner Jesse Wilson. The cars are "in pretty bad shape. You can see that they're completely, completely derailed from the track. They've been destroyed completely. The aluminum shell has been destroyed and they've been overturned completely."
The crash required a four-alarm response, including 120 firefighters and 200 police officers.
The six cars derailed in Port Richmond, a working-class part of Philadelphia's Great Northeast.
Witnesses said the train was going into a turn when it shook. People were thrown to the ground, "chairs inside the train became unscrewed and suitcases were falling on people," said Max Helfman, 19, of Watchung, New Jersey, who was on the train with his mother.
"My mother flew into me and I literally had to catch her," he said. "People were bleeding from their head. it was awful."
The train's engineer was injured and treated, and "either has or is giving a statement or report to the Philadelphia Police Department," Nutter said Wednesday. He initially called that person the conductor, then corrected himself at a later press conference.
He did not comment on other Amtrak personnel.
Nutter said Pennsylvania Gov. Tom Wolf ordered state flags to be flown at half-staff, and Nutter ordered the same in Philadelphia.
President Barack Obama released a statement Wednesday, saying in part, "Our thoughts and prayers go out to the families and friends of those we lost last night, and to the many passengers who today begin their long road to recovery.... Philadelphia is known as the city of brotherly love -- a city of neighborhoods and neighbors -- and that spirit of loving-kindness was reaffirmed last night, as hundreds of first responders and passengers lent a hand to their fellow human beings in need.
NTSB Launches 'Go Team'
Seven investigators with the NTSB arrived at the scene Wednesday morning, and more are on the way from Washington, D.C.
"We do not know what happened here," Nutter said. "We do not know why this happened. We are not going to speculate about it."
The train's data recorder has been recovered and will be analyzed at an Amtrak operations center in Delaware, Sumwalt said. Data recorders capture speed, applications of the brake, and use of the throttle, horn and bell, among other pieces of information, Sumwalt said. The train had a forward-facing video camera on its front.
Investigators will also examine the track, train signals, the operation of the train and other conditions that may have contributed to the crash.
Sumwalt said around 10:30 a.m. Wednesday that investigators are gathering training records of crew members and have gotten an overview of the scene but have not yet begun documenting the wreckage.
Search and recovery efforts are taking precedence over the investigation, he said. The NTSB's first priority will be to collect "perishable evidence" that would be lost due to the passage of time.
"We're here... to learn from these things and prevent them from happening again," Sumwalt said.
He said the NTSB hasn't talked to the engineer year because he "went through a very traumatic event" and we want him to "convalesce."
He said they don't have exact figures yet of when the train first reached 106 mph, saying that investigators will develop a timeline in the future.
The locomotive and all but two passenger cars are being removed to a secure location. Investigators will be at the crash site for the next few days, striving to capture evidence before conducting analysis.
The NTSB has released the track to Amtrak so the company can begin rebuilding, Sumwalt said late Wednesday afternoon.
Investigators are planning to interview train crew members, other personnel and passengers, conduct a sight distance test, and test signals and braking system. They will also conduct a more detailed analysis of the data recorders, but Sumwalt said the current speed estimates will be very close to the final calculations, within about 1 mph.
"I feel like for just arriving on scene this morning, I feel like the preliminary information we have is robust, but we still have a lot to get," Sumwalt said.
A speed control system known as Advanced Civil Speed Enforcement (ACSES) is installed through most of Amtrak's Northeast Corridor, but not in the area where derailment occurred, Sumwalt said. The system is designed to keep trains below their maximum speed.
Sumwalt said he believes that had the system been installed, this crash would not have occurred.
Both U.S. senators from Pennsylvania, Bob Casey and Pat Toomey, toured the crash site Wednesday, which Toomey called a "horrific and heartbreaking scene."
Federal Railroad Administration records show there have been nine Amtrak derailments so far in 2015, compared to 28 in all of 2014 and 25 in 2013.
Another Amtrak train, bound for New Orleans, crashed on Sunday. That train struck a flatbed truck at a railway crossing in Amite, killing the truck's driver and injuring two people on the train.
In March, at least 55 people were injured when an Amtrak train collided with a tractor-trailer that was stuck on the tracks in North Carolina.
Amtrak: No Service Between Philly & NYC
Amtrak service is suspended Wednesday between New York and Philadelphia following the deadly derailment, and while Thursday's plan has not been finalized, Amtrak officials said it's likely that service between those cities will continue to be affected.
New Jersey Transit is honoring Amtrak tickets between New York City and Trenton.
Modified Amtrak service is operating between Washington and Philadelphia, Harrisburg and Philadelphia, and New York and Boston.
Other Amtrak trains are running between New York and Albany-Rensselaer; New Haven and Springfield, Mass., and other points, Amtrak said.
Amtrak has established a family assistance center in Philadelphia for family members of passengers and crew on the train.
Stay with News4 and NBCWashington for updates.