Compatibility adjustment between foreign standard rails and domestic fastener systems
- In what aspects are the compatibility problems between foreign standard rails and domestic fastener systems mainly reflected?
The difference in rail head width is a core problem. For example, the width of the European standard UIC60 rail head is 73mm, which is 3mm wider than that of the national standard 60kg/m rail, resulting in uneven distribution of elastic clip clamping force with a deviation of 15% - 20%. It is necessary to grind the side of the rail head to the adaptive size. The rail base slope angle is different. The rail base slope of American standard rails is mostly 1:40, while that of domestic ones is 1:20. Direct installation will shift the wheel - rail contact point, increasing the lateral force by 10% - 15%. It is necessary to add wedge gaskets under the 垫板 for adjustment. The deviation of rail web thickness affects the installation of the pressing plate. The thickness of the Russian standard rail web is 2 - 3mm thicker than that of the national standard, resulting in the pressing plate being unable to fit. It is necessary to mill both sides of the rail web to the design size to ensure the gap ≤0.3mm. The bolt hole positions do not match. The bolt hole spacing of foreign standard rails is inconsistent with that of domestic fishplates. For example, the hole spacing of Japanese standard JIS50 rails is 130mm, while that of domestic ones is 140mm, requiring re - drilling for adjustment.
- What are the specific measures to adjust the rail head size of foreign standard rails to adapt to domestic elastic clips?
A profile grinder is used to process the side of the rail head, reducing the width of the European standard UIC60 rail head from 73mm to 70mm. The grinding amount is controlled at 0.5mm/time to avoid overheating affecting the rail head performance. After grinding, the surface roughness Ra ≤3.2μm. The radius of the rail head arc is trimmed according to domestic standards. The fillet of the foreign standard rail head is mostly 13mm, while that of the domestic one is 12mm, which is achieved by numerical control grinding to ensure that the fitting degree with the elastic clip groove is ≥90% and reduce the loss of clamping force. For foreign standard rails with excessive rail head height (such as 2 - 3mm higher than the national standard), the top of the rail head is ground to the standard height, and at the same time, the cross - sectional area of the rail head is ensured not to decrease by more than 10% to maintain strength. After grinding, the clamping force test is carried out to ensure that the deviation of the elastic clip clamping force is ≤5%. Unqualified ones need to be readjusted until they meet the requirements of domestic fasteners.
- What are the specific measures for adjusting the rail base slope of foreign standard rails?
Installing wedge - shaped gaskets is a common method. The gasket slope is 1:20, with a thickness of 5 - 10mm. The rail base slope is adjusted through combinations of different thicknesses, so that the wheel - rail contact point returns to the center position. After adjustment, the lateral force is reduced by 10% - 15%, which can be used for ordinary railways. Milling the rail base to adjust the slope angle, mechanically processing the foreign standard rail base to directly mill a 1:20 slope with a processing depth of 0.5 - 1mm, ensuring that the surface flatness is ≤0.1mm/m. Heavy - haul railways prefer this method for better stability. Replace the adjustable under - rail pads, select pads with slope adjustment function (slope 0 - 1:10 adjustable), realize the adaptation of the rail base slope by rotating the pad angle, which is easy to install and suitable for temporary transition or small - batch laying of foreign standard rails. After adjustment, detect the wheel - rail contact position, check with the rail head grinding template. It is qualified if the contact point deviates from the center by ≤1mm, otherwise, it needs to be readjusted.
- What are the connection adjustment measures between foreign standard rails and domestic fishplates?
Redrill holes to match the hole spacing. Redrill foreign standard rails according to the hole positions of domestic fishplates. The hole diameter is 1 - 2mm larger than the bolt diameter (such as M24 bolts with φ25 - 26mm holes). The hole position deviation is ≤0.5mm. After drilling, chamfer to remove burrs. Use transition fishplates for connection. When the hole position difference between foreign standard and national standard rails is large (more than 10mm), use special - shaped fishplates with one end adapting to foreign standards and the other end to national standards. The length of the transition section is ≥100mm to ensure smooth load transmission. Adjust the bolt specifications. For large - diameter bolt holes of foreign standard rails (such as φ28mm), use thickened bolts (M27) with matching nuts to ensure that the preload meets the standard (≥200kN) and avoid connection loosening. After connection, detect the smoothness of the joint. The rail head height difference is ≤0.3mm, and the side flatness is ≤0.5mm, meeting the domestic track smoothness standard.
- What are the performance verification indicators after compatibility adjustment of foreign standard rails?
The clamping force deviation of the fastener system must be ≤5%. The clamping force tester is used for detection to ensure that the matching force between foreign standard rails and domestic elastic clips meets the design requirements. High - speed railways have stricter requirements (≤3%). The wheel - rail contact stress is evenly distributed. Measured by stress sensors, the maximum stress is ≤300MPa, and the stress concentration factor is ≤1.2, consistent with the full - line rails. The track dynamic response meets the standard. The vibration acceleration when the train passes is ≤30m/s² (high - speed railway) and ≤50m/s² (ordinary railway), with a difference of ≤10% from the national standard rail line. Long - term operation test: lay a 1km test section. After 1 year of operation, detect that the rail displacement is ≤1mm and the fastener loosening rate is ≤1%, proving that the compatibility adjustment is effective.