(AP) -- The lead investigator for the National Transportation Safety Board says the Amtrak train sped up for a full minute before it derailed at a sharp curve.
Board member Robert Sumwalt says a camera mounted on the front of the train shows it was going 70 mph 65 seconds before the video went dark.
By 16 seconds before the crash, the train had increased to 100 mph, soon reaching 106 mph right before entering a 50 mph section.
Investigators are still unsure why the train was speeding up.
Sumwalt says inspection records show no anomalies with the track, signals or train itself. It had left Philadelphia's 30th Street Station on time.
He says engineer Brandon Bostian has agreed to speak to NTSB investigators in the next few days.