An approach to monitor railway pantograph-catenary interaction with fiber optic sensors

With the increase of the speed in the railway operation, a particular care has to be addressed to the interaction between pantograph and catenary: the variation of contact force and, consequently, the contact loss probability increases. The contact between pantograph and catenary is an electromechanical contact and when a contact loss occurs electrical arcing phenomena arise. One of the most important effects of arcing phenomenon is the increase of wear for both contact wire and contact strip. The monitoring of contact force between pantograph and catenary in the high frequency range (up to values greater than 100 Hz) should be useful to put in evidence problems on the pantograph-catenary interface. In this work the use of fiber optic strain gauges, with FBG technology, to measure the pantograph-catenary contact force is discussed. This solution is insensitive to the electrical disturbances caused by the sparks and can be safely used in-line. Starting from a static and dynamic validation of the sensors, using as a reference traditional electrical strain gauges, a method to estimate the contact force was developed and tested.