Definition, hazards and formation of rail wave abrasion rail corrugation grinding machine

Rail wave wear basics

Rail wave wear referred to as rail wave wear, is a major type of rail damage.

Rail wave abrasion refers to the rail head tread along the length of the cyclical uneven hook plastic deformation and wear, so that the entire length of the rail presents a wave shape of the uneven.

Wave abrasion of the valley of the wave has obvious plastic deformation, so that the tread rolling wide or appear rolling edge, wheel and rail contact with the broadening of the light band. The amount of plastic deformation of the tread surface at the crest is obviously smaller than the trough, the contact light band is narrower.

Wave peak, wave valley tread surface light and dark degree of difference (such as the above figure). The wavelength of wave abrasion is the horizontal distance between two adjacent wave crests, and the wave depth is the vertical distance between adjacent wave crests and troughs.

Various types of railway wave mills

Metro lines: Operate trains with lighter axle weights, with more small radius curves and shorter station spacing. This results in frequent braking and starting of the trains, which generates rail abrasion at wavelengths of between 30 and 80 millimetres, with shallow depths of abrasion. The vibration frequency caused by this characteristic is high, typically above 200 Hz.

High-speed railway: There is no obvious correlation between the generation of rail abrasion and the line shape, whether it is a straight line, a gentle curve or a round curve section, the phenomenon of abrasion may occur. Rail abrasion is distributed discontinuously in many places, with the length of each abrasion along the longitudinal direction of the line varying from 10 to 15 metres. The wavelengths are short, typically 120 to 150 mm in the case of high-speed lines and 60 to 90 mm in the case of low-speed lines. Compared to metro and mixed freight and passenger lines, the depth of ballast wear on ballasted rails in high-speed railways is shallow, usually in the range of 0.04 to 0.10 mm.

For mixed freight and passenger railways: because of the higher axle weights of the trains, the wavelength of the rail wave abrasion is longer, typically in the range of 200 to 300 mm, and the depth of the wave abrasion is deeper, which results in a lower vibration frequency, typically in the range of 30 Hz.

During the manufacture, transport and laying of turnouts, some deviations in the geometry of the turnout inevitably occur. Under the continuous action of train load, these deviations may be further expanded. This situation not only reduces the comfort of travelling and aggravates the deterioration of the smoothness of the turnout area, but also poses a serious threat to the safety of travelling and leads to a decrease in the safe travelling speed.

Regarding the wave wear in the turnout area, the distribution of different wavelengths varies. Wave abrasion with a wavelength of 80 - 300mm mostly occurs in the curved strand of the turnout, and also occurs in the straight direction from time to time. Wave abrasion with a wavelength of 300 - 1000mm is mostly found in the lines operated by a single-size vehicle, and it may appear in the whole turnout area. Wave abrasion with a wavelength of 1000 - 2500mm is usually regarded as a gradual evolution of the initial unevenness formed after rolling the rail.

The impact of rail wave abrasion on the track and train operation

1. Serious damage to the track

(1) Accelerate ballast crushing. The track is subject to vertical force, and the ballast is crushed by extrusion.

(2) Empty hanging, white joints, slurry and mud increase. Joints empty hanging will make white ballast turn over to the track surface, is a typical feature of empty hanging, long-term empty hanging plus rain and snow will make the track form slurry bubbling mud.

3) Failure of track sleeper increase. Train through the crest of the rail sleeper vertical force increases, accelerate the failure of rail sleeper.

2. Other effects

(1) Wheel-rail adhesion bad. Locomotive drivers in the wave mill section in order to ensure traffic safety, to slow down. Due to the wave grinding track surface is not smooth, resulting in poor wheel-rail adhesion, increasing the running resistance of the train, increasing the power loss.

(2) Locomotive parts repair and replacement rate increases. As the train through the wave mill section vibration intensification, rolling stock parts damaged, resulting in loosening, fracture, increasing the workload of locomotive maintenance, bringing unnecessary economic losses.

(3) Derailment. Wave wear serious section, the train through the wave crest, the train impact increases, and through the wave valley when the force is reduced, the train's instantaneous load shedding is easy to cause derailment.

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