Background Information: Rail automation in mass transit systems - How does automatic train control work?

A trackside computer tracks all trains in the assigned section of line and calculates an appropriate movement authority for each train. As a result, trains are routed continuously and can run at shorter headways than when driven manually on sight. In fully automated mode, metro trains are driven by the Automatic Train Control (ATC) in combination with control and protection of the line by interlockings. To this end, the trackside computers are constantly exchanging data with the computers of the higher-level system in the control center and the computers in the train by radio. On board the train, the Automatic Train Operation (ATO) system replaces the metro driver and controls the train's speed. The ATO computer is monitored and, if necessary, corrected by the Automatic Train Protection (ATP) system.