Railway signalling devices are used to ensure the safety of trains running on the railroad network. With the passage of time, the technical state of railway signalling devices deteriorates. During the exploitation of these devices, processes dependent on changes in technical states and changes in exploitation states occur. Achieving the maximum efficiency in the operation of a railway signalling system requires a shift from traditional corrective servicing to preventive service based on ongoing diagnosis of the technical state of the devices involved in train movements. An even greater opportunity is provided by the introduction of mathematical modelling methods into the exploitation testing of railway signalling devices and the prediction of their basic reliability indices well in advance. The proposed method allows the exploitation strategies for the signalling systems to be changed from a service-life-based strategy to a current-technical-state-based strategy while ensuring the required safety level.