A detailed investigation of uplift and damping of a railway catenary span in traffic using a vision-based line-tracking system

Abstract

For electrified railways, the catenary dynamic behavior is critical to ensure a robust and steady current collection quality for electric trains. The current collection is achieved as the catenary directly interacts with the pantograph, installed on the car-body roof to provide an electrical current to the engine. Damping plays an essential role in numerical simulations of pantograph-catenary interaction, especially for multiple pantographs. However, damping estimation of existing catenary sections is recognised as a challenge, and only a few studies have been published with single values of damping estimations. This study aimed to estimate the spatially distributed damping of an existing catenary span through full-span uplift measurements using a vision-based line-tracking system (VIBLITE). A detailed study was performed at critical locations along the catenary span. Sixty-nine single/double-pantograph train passages were acquired during scheduled train operation. Time series of uplift and acceleration were obtained through a line-tracking image-processing technique. The uplift amplitude was statistically analysed, where the damping ratios were identified using the covariance-driven stochastic subspace identification (Cov-SSI) method. Finally, the spatially distributed Rayleigh damping coefficients were successfully identified to quantify the important spatial variation in energy dissipation within a span. Arithmetic averages of damping coefficients over all measuring locations were obtained and recommended for future numerical simulations.