Monitoring overhead line equipment

Computer modelling systems are used to optimise the overhead line equipment (OHLE) and pantographs for high-speed railways. This design technique enables cost-effective electrification to be implemented but the fault-tolerance of the resultant system is limited. The use of monitoring systems to monitor the condition of the OHLE and pantograph enables the detection of faults before catastrophic failures occur, thus preventing expensive and inconvenient delays to rail-borne traffic. Installation and correct use of such systems should enable high-speed electrified railways to operate reliably. The author briefly describes three monitoring systems. The first is the Brecknell Willis and Co. Pantograph Force Measuring Device (PFMD). This precision instrument is used by a fitter in a depot to determine whether he has completed pantograph maintenance work satisfactorily. The second is the AEA Technology Rail Panchex^(R) system, which measures the dynamic performance of a pantograph automatically, as a train passes through a suitably equipped trackside monitoring site. The third is the AEA Technology Rail OLIVE^(R) system which is capable of detecting overhead line imperfections automatically