How do you stop a train on time ?

To stop a train in time, two possibilities exist: a manual stop by the driver, and an automatic stop.
The driver will estimate the moment to start braking, using track signals and his own knowledge of the train and the line. During an automatic stop, measuring instruments, placed on the trains and on the tracks (wheel sensors, radars, odometer, beacon system, shock absorbers), record the speed, position and mass (degree of compression) of the train. Based on this data, the train can automatically evaluate when to begin braking.

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