Track pad function and selection knowledge
What is the core function of under-rail base plates?
The core function of under-rail base plates is to disperse the pressure of rails on sleepers and subgrade, avoiding damage caused by excessive local stress. It can absorb vibrations and impact forces generated by train operation, reduce track noise, and improve the surrounding environment. Adjust the track height through elastic deformation to ensure track smoothness and enhance passenger comfort. It can reduce wear between rails and sleepers, extending the overall service life of track components. It can adapt to different geological conditions, cope with foundation settlement or expansion, and maintain track structure stability.
What are the common materials of under-rail base plates?
Rubber base plates are the most commonly used material, with good elasticity and durability, and significant shock absorption and noise reduction effects. Plastic base plates include polyethylene, polypropylene and other types, with excellent corrosion resistance and insulation, and are lightweight and environmentally friendly. Steel plate base plates have high strength, can effectively disperse pressure, are suitable for heavy-haul lines, and some use special coatings to enhance corrosion resistance. Composite base plates combine the advantages of rubber, plastic and metal, with light weight, high strength, good shock absorption and strong environmental adaptability. Base plates of different materials are used in combination according to line requirements, such as composite base plates of rubber + stainless steel plates.
What are the performance indicators of under-rail base plates?
Static stiffness is a key indicator. The static stiffness of rubber base plates is usually 60±10kN/mm, which needs to be adjusted according to line requirements. The ratio of dynamic to static stiffness is ≤2.0 to ensure that the base plate can maintain stable elastic performance under dynamic loads. The peel strength of composite base plates is ≥4kN/m to prevent separation between different material layers. Shore A hardness is ≥65 to ensure the support force and wear resistance of the base plate. The insulation resistance is ＞5×10^6Ω to avoid short circuits in the track circuit and adapt to electrified lines.
What are the installation precautions for under-rail base plates?
Before installation, check whether the base plate has cracks, deformation and other defects to ensure qualified product quality. Measure the gauge and track levelness to ensure the accurate installation position of the base plate, in line with design requirements. The base plate must be aligned with the rail and sleeper, without offset or inclination, to ensure uniform force. Tighten the relevant bolts after installation to ensure the base plate is firmly fixed, with no risk of loosening or displacement. After installation, check the track flatness and make fine adjustments if necessary to ensure smooth train operation.
How to select under-rail base plates according to line types?
High-speed railways should select high-elastic rubber base plates or composite base plates, which have good shock absorption and noise reduction effects and improve ride comfort. Heavy-haul railways need to use high-strength steel plate base plates or high-stiffness composite base plates, which can withstand large loads and impact forces. Urban rail transit prioritizes rubber base plates with low noise to reduce impact on surrounding residents. Electrified lines need to select plastic base plates or composite base plates with excellent insulation performance to avoid circuit failures. In cold regions, base plate materials with stable low-temperature performance should be selected to prevent low-temperature brittle fracture and ensure winter use safety.