Realization of High-Precision Automated Rail Corrugation Measuring Based on Chord Method

In China, with the high-speed development of railway and increase of volume of transportation, rail corrugations become more and more severe. The causes of rail corrugation are many and varied: driving force, nature environment, the quality of steel material and so on. Rail corrugation is the main reason that generates noise and increases dynamic interaction force between rail and wheels. If can not be maintained in a timel y manner, rail corrugation will deteriorate the wheel-rail contact surfaces, reduce the life of rail and vehicle components, and increase the maintenance cost and safety risk. In this paper, we proposed the chord method to measure rail corrugation. This method acquires the chord offset value relative to the reference plane through three laser distance sensors, which are installed along the track direction and their intervals are 30mm and 300mm respectively. It then restores the real track irregularity using the transfer function corresponding to the chord offset value. The proposed method can effectively eliminate measurement errors caused by the railway mechanical structures, rail track undulation and other factors. Using proposed method, we can get high precision results on rail corrugation within the wavelength range of 30mm to 1000mm. Based on our statistical analysis of the actual measurement results, the measurement accuracy can get up to 0.05mm, which meets the demands of the track measurement and maintenance.