The functionality of the railway system largely depends on the safety, reliability, availability and the maintainability control-command and signalling infrastructure subsystems. The main characteristic of the safety-signaling devices installed on the railway network of the Republic of Croatia is an extremely heterogeneously technical and aged structure with a large proportion of the units in an advanced stage of wear. The organization of maintenance marks a disproportionate number of executive workers in certain units of the maintenance. Considering the current organizational and exploitative requirements, effective management of maintenance of the safety-signaling devices is a complex task for the infrastructure manager. This paper defines influencing factors and development guidelines to improve the maintainability the safety-signaling devices. The paper highlights the importance of improving the existing troubleshooting procedure and the way we monitor malfunctions of the safety-signaling devices by using the application system and describes the working version of the application SS_TK which is currently testing. An analysis malfunctions model of the safety-signaling devices is proposed and defines the basic weighting coefficients that allow to compare levels of reliability and availability of the equipment and maintenance efficiency of maintenance sectors. This analysis shows the practical application of the model. By following the phases of the model it is possible to identify risks and potential weaknesses of the "critical points" of the process of maintenance management safety-signaling devices, and consequently the current action focus on preventive action to reduce or avoid the risks. This is a prerequisite for improving the quality of the planning of priority projects on the maintenance, rehabilitation and modernization of the safety-signaling devices on the railway network of the Republic of Croatia.