Fiber optical sensor network embedded in a current collector for defect monitoring on railway catenary

In order to identify defects of the electrical infrastructure during train operation, a fiber Bragg grating based sensor system performs measurements of the distribution of short time force changes in vertical and horizontal (driving) direction between current collector and overhead contact line. The actual model calculations and the practical design of a 2-dimensionally arranged strain sensor network have been especially enhanced to the calculation of impact directions. The well-known advantages of fiber-optic sensors - embedding capability in the composite carbon/aluminum collector strip, multiplexing of distributed sensor networks, electrical isolation - are of particular importance for detection and characterization of fast impacts immediately at the position of incidence. Tests under everyday operating conditions with trains on high-speed tracks as well as under high load in mountain regions proved the application of this sensing technology. Problems and solutions for the sensor network embedment, the fast Bragg sensor interrogation algorithms, and actual lab test results with their application-orientated analysis will be presented.