Starting from the '90s, the traditional analog devices deployed throughout the entire Italian Traditional Fundamental railway Network (RFT) are being gradually replaced in favor of digital devices. The benefits coming from this decision are multiple and among others: the smaller overall size with respect to traditional systems, the faster reaction in case of failure, the remote management and the distributed diagnostic. To ensure the same grade of reliability in terms of security though, it is necessary to use high-reliability SIL4 electronic equipment and verify the correct functioning of the system components by the means of continuous testing, securing the system after a failure occurs.