Dynamic detection for the contact line gradient in electrified railway

In this paper, the importance of the contact line height and gradient in the electrified railway and the current inspection methods for the contact line height and gradient are analyzed, and then the dynamic detection system for that is deigned, which based on the laser phase ranging principle. The detection system is setting on the top of locomotive and a cooperative target is fixed on the pantograph; the laser system measures the height between the top of locomotive and the working pantograph by the cooperative target when the locomotive runs, and then the gradient of contact line can be calculated in real time when the locomotive's running information is provided. The laser phase ranging system uses the DFT method to calculate the phase difference, which can get the higher resolution than the method of the electronic phase demodulation and reduce the influence of the shift of laser intensity etc. The dynamic detection system works well to detect the contact line gradient, without influencing the normal operation of the locomotive, and the disadvantages of manual detecting and detecting car are avoided.