Smart sensor for detection of derailment on freight trains

In this paper a sensor node able to monitor the growth of a crack in a wheelset, by means of axle box acceleration measurements, is described and the first results of experimental field tests are presented. The sensor node is equipped with a wireless transmission system and a bimorph piezoelectric energy harvester. Moreover, the node is inserted in a specific suspension system, which allows the measurement of low frequency accelerations (around wheel revolution and its first multiples) and amplifies the energy recovered by the harvester. The first tests on a freight convoy along a traditional Italian railway line show that the designed sensor node is able to acquire, analyse and transmit data with a frequency which depends on the power needed by the operation cycle.