Terrorism
“A U.S. law enforcement official told CNN that so far, there is nothing to indicate the incident was an act of terrorism.”
http://www.cnn.com/2015/05/13/us/amtrak-derailment-possible-causes/
well there it is....
Of course they are not going to call it for what it is because it’s not politically correct to do so.
Just like the Germanwings pilot.