Definitions for "Automatic Train Control"
Keywords:  cab, atc, railway, brakes, wayside
(ATC) A term covering systems designed to assist the engineer and provide against mishandling or misinterpretation of signals. These systems range from simple cab warning systems to fully automatic control.
If a signal was passed at danger this device would automatically apply the brakes.
An early system invented by the Great Western Railway in 1910 to give drivers an audio warning of the status of the signal ahead.