Abstract: The contribution addresses the problem of software life-cycle, aspects and application of formal methods in functional specification, design and verification of real-time software systems in safety-critical applications. The target application thereunder aims to verify the critical parts of the designed interlocking system. The higher safety, reliability and minimized costs of the design can be achieved using presented techniques. Bidding for this a synchronous data-flow language Lustre has been used to verify safety properties of selected parts of the system. The introduced test-case has been implemented on distributed architecture of multiple single-chip microprocessors.