ASFA DIGITAL System is a semicontinue ATP System, being its main fuction to achieve a continues supervision of the speed of the train by the information read in the beacons.
ATP System controls the speed on startup and gives an over speed protection, free track control, stop announcement control, pre-announcement stop control, detour gait detection, stop control signals detection, protected detour gait detection, nonprotected detour gait detection, temporal speed limitation and event records.
The ATP system is programmed with different speed curves predefined by the Administrator of Railway Infrastructures. The speed curve for each railway section is stablished depending on the different signals received from the beacons. With these parameters, the ATP System indicates the speed of the train in each point of the railway line by the request of different signals defined and the representation of them in the different displays. In case of dismatch, the system activates the brakes of the train.
A sensor receives the frequency of the beacons and an aperiodic amplifier that generates permanent frequency, and these signals are sent to the control unit.
The Speed is calculated using a tachometer attached to the axle or a speed sensor in phonic wheel.
All the information is displayed to the driver: speed of the last control, effectiveness, last information of the ATP, overspeed, etc. There are also an additional Buttons Panel which is used for recognition of signals by passing through the signals.