The wave motion propagation characteristics in overhead contact line greatly affect the contact force fluctuation of pantograph. The transfer coefficient of contact wire wave motion at hanger points and the damping coefficient of contact wire are two of the most influential characteristics. In this study, those propagation characteristics are theoretically analyzed and measured in a real overhead contact line by the wave separation measuring method and spectrum analysis method. It is confirmed that the measured values of the transfer coefficients at a hanger point are mostly in agreement with theoretical values, and the line flexural rigidity is influential on the transfer coefficients even at low frequencies. The reflection coefficient at a rubber-damping hanger is smaller than that at an ordinary hanger. The damping factor of tensioned wire is represented as the sum of two terms, one proportional to the tension, and the other to the elastic modulus. The measured value (loss factor) of contact wire is about 4x10^-4, and that of the stranded wire (messenger wire) is higher than that of contact wire.

Copyright (c) 2002 Railway Technical Research Institute