A modular and integrated on-board system for freight train condition monitoring: design approach and testing

Condition monitoring is becoming an essential tool in the railway industry, increasing the efficiency of vehicle maintenance. This is particularly critical in the case of freight trains since most wagons are still not equipped with sensors or wired. The proposed research work aims at developing a monitoring system with two main purposes: to apply to different wagon typologies and to be an integrated solution for the monitoring of the different mechanical subsystems of the vehicle. The focus is put on the energy harvesting to suitably power supply the wireless sensor nodes and on the performance enhancement for the identification of possible faults in the braking plant. The design of the monitoring system has been driven by an empirical model of the braking plant realized also to support the analysis of experimental data collected by the monitoring devices in the diagnostic stage. Moreover, a CFD analysis was performed to optimize energy harvesters (i.e. micro wind turbines) positioning on the wagon to enhance their efficiency. In the paper, it is shown how the numerical tools allowed to suitably design the wireless monitoring system, which is adopted in an experimental campaign aiming at collecting a database for the validation of condition monitoring algorithms.