Methodology for the monitoring, control and warning of defects for preventive maintenance of rails

摘要

The preventive maintenance of rails is necessary for safe, successful and economical railway performance and operations. Rolling contact fatigue (RCF) is one of the main issues that concern the head of the railway. Progressively, RCF defects can propagate inside the material with the risk of damaging the rail, and thus they need to be monitored, categorized, evaluated, and treated through a comprehensive maintenance system. In a previous work with the Athens Metro, an innovative monitoring system was developed based on the capability of non-destructive techniques, such as IR thermography, to inspect and identify defects at early stages and reveal the activated paths of fracture (Moropoulou A., Avdelidis N., et al. Thermosense XXVII, 5782, 371-378, 2005). In the present work with the Athens Piraeus Electric Railways S.A. this system is further integrated into a complete system consisting of three components. The surveillance component identifies the rail defects and includes non-destructive techniques, such as visual inspection, infra-red thermography, ultrasonics, fiber optics microscopy, and ACFM. The data management component receives information from the various defect identification techniques, categorizes them and stores them for further use. The defect warning component uses risk indices such as defect level indices, defect extent indices, and risk threshold values, in order to evaluate the significance of the observed defects. All three components are part of a decision making system that monitors the development of defects, warns for significant threats and schedules rail maintenance.