Automatic Train Protection

Overview
An Automatic Train Protection (ATP) system uses a target speed indication and audible warnings to warn the train driver if they are likely to exceed a speed profile that will cause the train to pass a red (danger) signal or exceed a speed restriction. The system will apply the brakes if the driver fails to respond to these warnings. The system takes into account the speed and position of the train relative to the end of its "movement authority" in issuing the warnings and applying the brakes.