Knowledge on the Relationship between Rail Plate Installation Accuracy and Track Smoothness
How does the position deviation of pressing plate installation affect track smoothness?
When the lateral position deviation of the pressing plate exceeds ±2mm, it will cause uneven lateral force on the rail, resulting in lateral vibration when the train passes, affecting running smoothness. Excessive longitudinal position deviation will make the spacing between adjacent pressing plates inconsistent, uneven distribution of rail support points, and the risk of local subsidence. The alignment deviation of bolt holes is ≤1mm; if the deviation is too large, the pressing plate will be twisted and deformed after the bolt is tightened, indirectly leading to uneven rail surface. On curved lines, the deviation of the pressing plate position will change the guidance of the rail, increase train wheel-rail wear, and reduce smoothness. Long-term existence of position deviation will aggravate rail deformation, resulting in excessive gauge deviation and affecting driving safety.
What is the control standard for the height difference of pressing plate installation?
The height difference between the two side pressing plates on the same sleeper is ≤0.3mm to ensure uniform force on the rail and avoid rail surface inclination. The height difference of pressing plates on adjacent sleepers is ≤0.5mm to prevent step-like vertical deviation of the rail surface and affect the stable operation of the train. High-speed railway lines have stricter requirements for height difference, controlled at ≤0.2mm, adapting to the harsh requirements of high-speed trains for smoothness. Height difference detection needs to use a precision level, measuring at two places: the top of the pressing plate and the bottom of the rail, and taking the average value as the judgment basis. If the height difference exceeds the standard during installation, it needs to be corrected by adjusting the thickness of the base plate, and it is forbidden to directly knock the pressing plate to force leveling.
How to control gauge accuracy through pressing plate installation?
The gap between the pressing plate and the rail side should be controlled at 0.5-1mm. Excessively large gaps are prone to cause lateral displacement of the rail and excessive gauge deviation; excessively small gaps will limit the thermal expansion and contraction of the rail and cause stress concentration. A gauge ruler should be used for real-time measurement during installation to ensure that the gauge deviation is within ±1mm, and the curved line is adjusted according to the superelevation requirement. Adjustable pressing plates are adopted to accurately control the gauge by adjusting the lateral position of the pressing plate, adapting to the gauge standards of different lines. The bolt tightening torque must be uniform to avoid rail deviation caused by excessive unilateral torque and affect gauge accuracy. Regularly check the lateral displacement of the pressing plate, and adjust the gauge deviation in time to ensure long-term use accuracy.
What track smoothness problems will be caused by improper pressing plate installation?
Failure to compress the rail by the pressing plate will cause the rail to move up and down under train vibration, resulting in dynamic vertical deviation of the rail surface and affecting smoothness. If the pressing plate is not closely attached to the rail and there is a gap, the rail support will be unstable, and the train will bounce when passing. Skewed placement of the base plate during installation will cause the pressing plate to be stressed and tilted, indirectly leading to rail surface distortion and poor wheel-rail contact. Improper selection of pressing plate material, insufficient hardness will cause permanent deformation, making the rail support point sink and form a low-lying rail surface. The accumulation of installation deviations of multiple pressing plates will lead to excessive rail surface smoothness indicators, increased train running noise and reduced comfort.
What special requirements does high-speed railway lines have for pressing plate installation accuracy?
The lateral position deviation of pressing plates for high-speed railway lines is ≤±1mm, and the longitudinal position deviation is ≤±1.5mm, which is higher than the precision standard of conventional railways. The height difference is controlled at ≤0.2mm to ensure that the rail surface smoothness meets the requirements of 350km/h operating speed. The contact area between the pressing plate and the rail is ≥98% to avoid uneven force caused by local suspension. Maintenance-free pressing plates are adopted, which do not need frequent adjustment after installation to ensure long-term precision stability. After installation, dynamic smoothness detection is required, and the rail surface irregularity is ≤1mm/20m through the test of the track inspection car, meeting the high-speed railway operation standard.