"I was thinking that if the head ends kept pulling the deceleration may not be so abrupt. Eventually the train has to be stopped but sudden application of full braking may not be the best route."
So noted in the Youtube video. He mentions letting the train coast for awhile, and then maybe gently braking (as I recall). That's pretty much what the Palestine train did, in that he was already in dynamic because of going downgrade. If he took it off of dynamic, it would speed up. Not the goal in mind. Hence more dynamic.
"You're right, with EP braking, cars behind the derailment could brake while engines ahead could pull."
I don't think so, at least when the train is still in one piece. All EP braking does is get the braking action to commence sooner. Without it, the signal to activate brakes has to travel down the air line. That is not as fast as electricity. With EP, the brakes all go on together. With regular air, it takes "awhile".
After the train has broken apart, it's pretty much all over. As I said, you'd probably save a couple of cars. And that would depend on transmitting signals to cars with the train broken apart. If it uses wires, that wouldn't work. If it uses wireless, it would have to potentially jump past the crashing cars--might not make it.
What EP is good for is running at higher operating speeds, because you get more efficient brake application--RIGHT NOW! You don't have to anticipate as much. Much of railroad operation is anticipation--you're controlling thousands of tons. Sorta like operating a large ocean going ship. But in a straight line.
spsalso