Originally Posted by
Traveller
For those of us that don't work in the field, what is PTC? I did google, but I still don't know.
Positive Train Control. Basically, it's an automated system that will apply the brakes on the train unless it receives a signal indicating that it's okay to proceed at speed. In situations where an engineer misses a speed restriction sign or a restricting signal, it would apply the brakes automatically to avoid entering a track section at too high of a speed.