Real time monitoring and wear estimation of railway track with FBG sensors

In this work we present the results of a field trial with a FBG sensor array system for the real time monitoring of railway traffic and for the structural health monitoring of both the railway track and train wheels. The test campaigns are performed on the on the 2nd line of Milan metropolitan underground, employing more than 50 FBG sensors along 1,5 km of the rail track, where the trains are tested during daily passenger rail transport, with maximum speeds roughly of 90 km/h. The measurements were continuatively performed for over six months, with a sampling frequency of about 400 Hz. The large amount of data/sensors allow a rather accurate statistical treatment of the measurement data and permit, with dedicated algorithms, the estimation of rail and wheel wear, key traffic parameters such as the number of axles, the train speed and load, and, in the next future, the detection of localised imperfections.