All of the “positive train control” systems in the world can’t overcome the laws of physics. Going 106 on a curve rated for 50 mph was a guaranteed disaster. The real question is how many other AMTRAK engineers have been speeding around those curves? Wouldn’t surprise me to discover some sort of informal competition, to see who could make the fastest DC-New York run, and who could take the curve at the highest speed.
I’ve been visiting a few railroad message boards in the wake of this accident; it appears AMTRAK will take applicants off the street—with no previous rail experience—and train them as engineers. In fact, most experienced freight engineers won’t take an AMTRAK job because they lose all seniority when they make the move.
Ideally, if the train is about to cross the speed limit, the system will automatically apply the train’s brakes (and maybe also disengage engine power).
As envisioned it is a grand scheme indeed. When under full PTC governance the train is running in a “Mother may I” mode. If the computer systems on board are not totally assured that track and train conditions are OK for the train to proceed, the train will brake.
The known dangers are so small — modern trains have such a good safety record — that this is known to be vast financial overkill.
Actually this is the exact problem that positive train control is for. The system knows when the train is approaching a lower speed zone, knows how fast the train is going, and can apply the brakes to force the train to reach a safe speed. Or to come to a complete stop if a signal is red, etc.