INVESTIGATION: NTSB confirms train traveling in excess of 100 mph

NEW YORK (WABC) -- It is still too early to tell what caused the train to fly off the tracks, but one of the deadliest passenger rail accidents in history occurred near the exact same spot more than 50 years ago.

A faulty axle was to blame in that case, but other factors this time are raising early concerns about the train's speed.

Daylight made all too clear what the death toll had already revealed, that whatever caused the derailment of Amtrak 188 required tremendous force, enough to topple multi-ton rail cars and severely mangle one.

"They've been destroyed completely," Philadelphia Fire Commissioner Derrick Sawyer said. "The aluminum shell has been destroyed and overturned completely."

Senator Charles Schumer said he believed speed was the likely cause, citing that the limit was 50 miles per hour but that the initial report indicates the train was traveling much faster.

An analysis by The Associated Press of surveillance video just before the crash indicates that the train was traveling about 107 miles per hour as it approached the curve.

The video shows the train -- which was roughly 662 feet long -- passes the camera in just over five seconds. But AP found that the surveillance video inexplicably plays back slightly slower than in real time. So, adjusting for the slower playback puts the train's estimated speed at 107 miles per hour. The surveillance camera was located at a site just before the bend in the tracks.

At an afternoon news conference, National Transportation Safety Board member Robert Sumwalt said the engineer, 32-year-old Brandon Bostian of Queens, applied the emergency brakes moments before the crash, and that the train was traveling at 106 mph when the engineer hit the brakes.

The engineer, Bostian, reportedly had a good record, and the tracks were inspected on Tuesday.

Another early clue may come from passengers on the train, one a reporter from New York City, Jillian Jorgensen, who tweeted that just before the derailment she "felt like the train hit the curve going too fast, we banked hard right, immediately obvious something was wrong."

Speed, according to former federal rail signal inspector James Sottile, will be an immediate focus for investigators.

"If not a broken rail or broken wheel or sabotage to the car, then it was over-speed, similar to what happened at Spuyten Duyvil," he said.

He was referring to the rail curve in the Bronx where four passengers died in 2013 when a Metro North train travelling at excessive speed derailed.

In the Amtrak derailment, it's too early to tell if speed was a factor. But there appear to be similarities, including a track curve. The NTSB has already sent the black box from the train locomotive to a lab for analysis, and they'll also be looking at video showing the exact point when the train flew off the tracks.

"We have forward-facing camera that's in the head end of the locomotive, front end of the train," NTSB chair Robert Sumwalk sait. "Event recorders can give us information on speed, braking, throttle, engineer sounding horn, it can give a lot."

This section of the Northeast Corridor still does not have positive train control, which automatically slows down the train if it is going too fast approaching a curve.

This crucial safety technology was absent in the Metro North accident, as well.