 The trains ' speed are controlled by an automatic train protection ( ATP ) system . The speed codes are transferred from the ATP points in the infrastructure , using 75 hertz pulses in the tracks . The trains pick up the signals via antennas . The speed codes are 15 km / h ( 9 mph ) , 30 km / h ( 19 mph ) , 50 km / h ( 31 mph ) and 70 km / h ( 43 mph ) . They are communicated to the engineer via signals in the driver 's cab ; in addition , the system will automatically reduce the speed , should the limit be exceeded . The driver can put the trains in an automatic mode , where the train itself adjusts its speed to the limit . The driver is always responsible for starting and halting the train at stations . 
