The mechanism of corrugation phenomenon on rolling surfaces. (1st report. Development of corrugation by experiment).

2019

Rail corrugation is a phenomenon in which roughness patterns of approximately regular wavelengths are formed on the rail running surface by trains running, and causes the vibration and the noise. Therefore, in this paper, we analyze the amplification factor of roughness amplitude using a model that takes into consideration the interaction between the track and the vehicle, and clarify the growth mechanism and the wavelength determination mechanism of the rail corrugation. As a result of the theoretical analyses, it is indicated that the essential factors of growth of the corrugation are (1) interference of rail wave motion between the front and the rear wheels of a bogie of the vehicle, (2) anti-resonance phenomenon of the elastic support of the track system, (3) anti-resonance phenomenon of the total system of the track and the vehicle, and (4) anti-resonance phenomenon of the vehicle system. In addition, as a result of examing the rail corrugation measured on the commercial lines, it is confirmed that the causes of the corrugation occurrence are the above mentioned (1),(2) and (3) factors, and that the measured wavelengths almost agree with the theoretical values.

Theoretical analyses of growth mechanism of rail corrugation

Aboshi

2019

Simulation analyses of progress process of rail corrugation

Aboshi

2019

Rail corrugation is such phenomenon that roughness patterns of approximately regular wavelengths are formed on the rail running surface by trains running, and cause the vibration and the noise. In the previous papers of ours, we have already explained the growth mechanism and the wavelength determination mechanism of the rail corrugation from the dynamic point of view and verified their validity by comparing them with the field data. In this paper, we report the results of simulation analyses of the characteristics of each step of formation, growth and saturation of the rail corrugation using a discrete elastic support model close to the actual track. As a result of the simulation, the following are confirmed : (1) at the formation step, by providing a minute and irregular wheel load fluctuation, rail surface roughnesses are formed with such wavelengths that their amplification factor of roughness amplitude is maximal and greater than 1.0. (2) at the growth step, as the contact length of the wheel / rail becomes longer, growth of roughness of the short wavelength is suppressed. (3) at the saturation step, when the roughness amplitude increases and the wheel loses the contact with the rail, the growth is suppressed and the roughness amplitude saturates. Based on these results, we present the progress process of the rail corrugation and the ways to approach the countermeasures.

Development of rail surface roughness continuous measurement trolley using asymmetrical chord method and application for rail corrugation measurement

Kajihara

Shimizu

et al. 2019

Rail corrugation is a periodic rail surface roughness that is formed as the rolling stock runs repeatedly on the rail. The rail corrugation occurs in various track alignment and track structures, but the generation mechanism and wavelength determination mechanism are often unknown. Therefore, in this paper, in order to measure the rail surface roughness of rail corrugation in detail, we have developed a trolley that can measure rail surface roughness continuously regardless of moving speed of the device. At that time, the asymmetrical chord method widely used in track geometry cars was adopted as a measurement method of the rail surface roughness in the longitudinal direction of the track. In this way, we considered to measure the rail surface roughness with any wavelength with high accuracy, and verified the measurement accuracy. Finally, we indicated that measurement cases at commercial lines, and the prospect of how to use the developed trolley.