Positive train control ties the locomotive's computer to GPS, wayside signal data and the dispatcher's back office, so it knows the train's location, its speed limits, its authority and any work zones ahead. If the engineer fails to slow down or stop in time, PTC first warns and then makes a penalty brake application. Federal law requires it on main lines carrying passengers or toxic-by-inhalation hazmat, and crews talk constantly about whether it initialized before departure.
PTC won't initialize on the lead unit, so we're sitting here until the help desk pushes our consist again.
Also heard as
- positive train control
Related terms
Alerter
A cab safety device that applies the brakes if the engineer stops moving the controls or pressing its reset.
CTC
Centralized traffic control: signals and switches controlled remotely by a dispatcher who routes every train.
Restricted speed
A speed slow enough to stop within half the distance you can see, used whenever the track ahead may be occupied.
Consist
The makeup of a train, listing its locomotives and cars in order with weights, loads and hazmat.