Monitoring of railway wheel diameters by means of a Wheel Impact Load Detector

Nowadays, various railway components are checked by numerous sensors, in workshops and in-service. Railway wheels are critical components, which their health status directly and indirectly are monitored. The Wheel Impact Load Detector (WILD) is a widespread commercial monitoring system, which exploits one or more strain sensors to detect defective wheels using wheel-rail contact force measurement. The objective of the research described in this paper is to use the WILD to measure the wheel diameter. This trait enhances the WILD ability to monitor more features of the wheel condition using the same system. Each wheel has its unique condition along its circumference, which causes a unique pattern of contact force, replicated in every revolution. By having the wheel diameter, the measured impacts can be mapped to the corresponding position over the wheel circumference. To achieve this purpose, a new configuration of strain sensors was proposed and the required algorithm for data filtration and processing was developed. To evaluate this method a set of simulation was carried out and the effect of different parameters such as sensor number, filter threshold, defect size and sensor noise were investigated. As the main result, the capability of the WILD for wheel diameter monitoring was proved.