The Amtrak wreck is getting curiouser and curiouser, as they say, especially if this train was actually accelerating at the point of derailment, as is now being "reported" by some outlets.

What is the grade on this segment: ascending or descending? And, by how much? What is the usual procedure, to use train air, or dynamic braking, when approaching this speed restriction......? Or is this some kind of computer operated blended braking combination?

And, finally has it been confirmed with "data" that the engineer did, in fact, big hole the train at some point immediately before the derailment, as one report suggested?

The actual event recorder should record all of this.

Several things come to mind, like what happened at La Cuesta..... when it was determined that the consist was actually in power, instead of dynamic braking.....

Also, it is still my understanding that if he did put it into emergency, the dynamics would cut out...which could explain a run out, especially, if for any reason, the trains air brake connectivity was somehow compromised, and the train was not braking as it should.

Or is it just good old fashioned human failure? And, did they have inward and outward facing camera's installed on this new unit?

It's going to be yet another interesting report to read.

And, yes, a proper PTC system would have kept this from occurring, assuming we are not dealing with some other system failure or tampering with the braking functions.