Automatic train control (ATC) is a general class of train protection systems for railways that involves a speed control mechanism in response to external inputs. For example, a system could effect an emergency brake application if the driver does not react to a signal at danger. ATC systems tend to integrate various cab signalling technologies and they use more granular deceleration patterns in lieu of the rigid stops encountered with the older automatic train stop (ATS) technology. ATC can also be used with automatic train operation (ATO) and is usually considered to be the safety-critical part of a railway system.
Japanese-style ATC cab signalling indicator
A Tokyu Corporation train with ATC-10 indicator operating under normal conditions
The said ATC-10 indicator with ORP (Over Run Protector) engaged near the end of the ATC coverage area
Speedometer in a 0 series driver's cab, showing the ATC cab lights on top of the speed indicators
A train protection system is a railway technical installation to ensure safe operation in the event of human error.
Berlin S-Bahn train stop in its engaged (left) and disengaged (right) position
Trackside magnets for very simple data communication. Outside and middle of track: Integra-Signum, other two (yellow) magnets: ZUB
