Railway catenary tension force monitoring via the analysis of wave propagation in cables

Abstract

The tensioning forces applied to the contact wire in a railway catenary system influence the performance of the line. In this paper, a method to monitor the status of such tensioning forces is proposed based on the dependency that the waves that propagate through a tensioned wire have on the forces that pull the wire itself. A novel analytical formulation for the propagation of waves in a tensioned wire was proposed, and it was used to obtain the vertical acceleration of the wire when an external force acts as a concentrated input. The analysis of the acceleration with a moving standard deviation allowed a method to be defined for the generation of an index that describes the trend of the tensioning forces. The method was then tested on the wire accelerations obtained with laboratory tests and, afterwards, on the accelerations recorded on a contact wire of an electric railway regularly in operation and excited with the same kind of input.