This CNN article states that this was Amtrak's 9th derailment this year? Did I miss some of them? A quick wikipedia search reveals only the Halifax, NC derailment where an ***** truck driver got in the way. Amtrak would be running out of equipment if there were that many wrecks.
http://www.cnn.com/2015/05/13/us/philadelphia-amtrak-train-derailment/index.html
There's lots of little ones that hardly anyone hears about. The Cardinal derailed on the NEC here in Odenton earlier this year when a wheel broke. All cars remained upright and nobody was injured, the track was OOS for about a week to get things cleared up.
The AP came up with 107mph using maths from the surveillance footage posted earlier. They noted that the playback in the footage is slightly slower then real-time.
peter
I think that's a little high, if I have the train length right (I think so), then it would take a time of 4 seconds. Looking at the timer in the corner (avoiding any issues with playback speed) I make out closer to 5. Maybe 4.5, which would put it around 100. Still, in the ballpark, and roughly twice as fast as it should have been going.