Well, yes.
Once we knew the speed it eliminated bombs, derailing by external means, debris - a host of other externals.
The thing that now needs to be determined is how that (speed) occurred - intentional, accidental, or catastrophic failure of equipment...
He did it.Had to throw it into gear 3 time to get to 100 miles per hour.He’s gay.His facebook page has been scrubbed to 2014.Where’s his boyfriend that he wanted to marry.Suicide and change of mind.Also distubed-penis pic’s and shaving pubic hair and flushing down toilet video.Not normal.
The two questions that come to my mind when I think about it being mechanical failure.
1) Why did he not call this out over the radio to dispatch/other trains to let them know of a possible runaway train? He seemed to have plenty of time to do so before the crash
2) If it was a system failure that caused it to speed up on its own, why did he not hit the emergency brakes when he first noticed it happening? We know they worked, since he hit them at the curve.