PHILADELPHIA -- The investigation into the deadly Amtrak crash is in its early stages, but late Wednesday Robert Sumwalt of the National Transportation Safety Board said the investigation is increasingly focusing on the train's speed in the moments before it went off the rails.
"Maximum authorized speed through this curve was 50 mph," said Sumwalt. "When the engineer-induced brake application was applied, the train was traveling at approximately 106 mph. Three seconds later, when the data to the recorder is terminated, the train speed was 102 mph."
The NTSB said it has not yet spoken to the train's engineer. Earlier, Philadelphia's mayor said the engineer was treated for injuries suffered in the crash and then taken to a police station, but the Philadelphia Police Department said he declined to make a statement before leaving the station with a lawyer.
CBS News has learned the engineer's name is Brandon Bostian.
What he isn't saying, the train's event recorder and front dash camera may reveal.
"Our mission is to find out not only what happened but why it happened so that we can prevent it from happening again," Sumwalt said.
The engine and all seven passenger cars flew off the tracks in the violent derailment. A law enforcement official told CBS News there is no evidence of terrorism or sabotage.
Pennslyvania Sen. Pat Toomey toured the crash site Wednesday afternoon.
"It's a horrifying scene," said Toomey. "There are train cars that are completely unrecognizable as train cars. They've been destroyed, completely destroyed."
Investigators will also be looking at the aging cars themselves. They date from the 1970s. Pictures from inside the train moments after the crash show luggage thrown from open shelving. Passengers were tossed as the train tumbled, raising questions about the need for seatbelts on trains.
Toomey said he needed to know more before saying it was time to talk about phasing out some of the older Amtrak cars.
"Well that's certainly something we want to understand, was that a contributing factor to either the derailment or injuries or deaths that followed," he said.
Amtrak is in the process of installing mandated techonlogy that would allow it to automatically slow down a speeding train. The deadline for that is the end of the year.