A fully redundant system
The metro system is fully redundant from the intelligent system core software and hardware up to data communication. The CPU processors of the system are internally redundant based on the two-out-of-two architecture which guarantees the highest safety integrity level and availability. The availability is further enhanced by the built-in features of the system platform that allow CPUs and all active modules to be duplicated, thus operating in full hot-standby. Consequently, a failure of one module does not cause failure of the entire interlocking.