Infographic: How positive train control works
Positive train control uses sophisticated electronics to monitor trains and take control of them if necessary to prevent collisions, derailments and other accidents.
Before a trip, data about speed limits, the track, construction zones, locations of other trains, etc. are loaded wirelessly.
Data
En route, the train’s position and speed are tracked via GPS. Signal status, broken rails, curves, etc. come in from wayside devices. Using these data, the system tells the engineer when to adjust speed.
Wayside device
If the engineer doesn’t act, the system takes over, adjusts speed and, if necessary, brings the train to a stop.
Red light
Before a trip, data about speed limits, the track, construction zones, locations of other trains, etc., are loaded wirelessly.
Data
While en route, the train’s
position and speed are tracked via GPS. Signal status, broken rails, curves, etc., come in from wayside devices. Using this data, the system tells the
engineer when to adjust speed.
Wayside device
If the engineer doesn’t act, the system takes over, adjusts speed and, if necessary, brings the train to a stop.
Red light
Sources: Federal records and interviews with rail safety experts. Graphic is schematic.
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