Integrated Matching Technology and Overall Adaptation Scheme for Different Rail Fastening Systems
What are the core integrated matching technologies for the fastener system of high-speed ballastless tracks?
The fastener system of high-speed ballastless tracks has extremely high requirements for stability and precision, and the core of integrated matching technology is to achieve "high-precision component adaptation + uniform force distribution". First, ensure the dimensional accuracy of each component. The forming deviation of the elastic strip is controlled within ±0.2mm, the matching gap between the contact groove size of the pressure plate and the rail base is ≤0.3mm, and the thread precision of the bolt reaches grade 6g, avoiding uneven force caused by dimensional deviations. Second, optimize the force matching relationship of the components. The vertical preload of the elastic strip is designed to be 12kN, and the lateral locking force of the pressure plate is designed to be 8kN. The force ratio of the two is controlled at 3:2. This ratio can balance the vertical and lateral constraints of the rail and reduce component damage caused by wheel-rail impact. At the same time, the stiffness matching technology of elastic pads is adopted. According to the track bed stiffness of the ballastless track, an under-rail pad with a stiffness of 60kN/mm is selected, so that the pad stiffness and track bed stiffness form a gradient match, improving the vibration reduction performance of the system. Special tooling positioning is used during installation to ensure that the installation position deviation of the elastic strip and pressure plate is ≤0.5mm, ensuring that the stress points of each component are accurately aligned. In addition, a digital matching file of the fastener system is established, recording the component model, installation parameters and stress data of each section of the line, providing an accurate basis for later maintenance.
What is the anti-fatigue integrated matching scheme for the fastener system of heavy-haul ballasted tracks?
The fastener system of heavy-haul ballasted tracks bears large loads and strong vibrations, and the core of the anti-fatigue integrated matching scheme is to achieve "high-strength component matching + uniform load transmission". First, select high-strength integrated components. The elastic strip is made of 55SiCrA high-strength spring steel, the bolt is made of 10.9-grade alloy steel, and the pressure plate is made of Q345B quenched and tempered steel. The strength grades of each component are matched to avoid system failure caused by insufficient strength of a single component. Second, optimize the load transmission path. By adjusting the contact angle of the pressure plate, the lateral load is smoothly transmitted from the rail base to the sleeper, and then diffused to the subgrade through the ballast, reducing stress concentration at the component connections. At the same time, a double-layer pad stiffness matching design is adopted. The upper under-rail pad is a polyurethane pad with a stiffness of 80kN/mm, and the lower layer is a rubber pad with a stiffness of 40kN/mm. The stiffness gradient of the double-layer pad can effectively buffer the impact load of heavy-haul trains and reduce the fatigue damage of components. The torque-angle dual-control method is used during installation to ensure uniform preload of the bolts, consistent deformation of the elastic strips, and avoid force deviation caused by uneven deformation of the elastic strips. In addition, the fastener system is regularly inspected for fatigue, and ultrasonic flaw detectors are used to detect internal defects of elastic strips and bolts every 6 months, and fatigue-damaged components are replaced in a timely manner.
What is the compatible integrated matching technology for the fastener system of ordinary-speed mixed-traffic tracks?
Ordinary-speed mixed-traffic tracks need to meet the operation requirements of both passenger and freight trains. The core of the compatible integrated matching technology of the fastener system is to achieve "wide working condition adaptation + low-cost maintenance". First, adopt modular component design. Divide the fastener system into elastic strip modules, pressure plate modules and pad modules. Different modules can be flexibly replaced according to the load changes of the line. For example, replace high-strength elastic strips in sections with dense freight trains, and replace vibration-damping pads in sections with dense passenger trains without replacing the entire system. Second, optimize the compatible parameters of the components. The preload of the elastic strip is designed to be adjustable in the range of 8-12kN, the contact groove of the pressure plate is compatible with the rail base sizes of various rail models, and the stiffness of the pad is designed to be adjustable from 30-50kN/mm, so that the system can adapt to the operation of trains with different axle loads. At the same time, standardized installation interfaces are adopted. The installation dimensions of each component comply with national standard general standards, facilitating batch procurement and rapid replacement, and reducing maintenance costs. In addition, establish a working condition adaptation model of the fastener system, and calculate the optimal component matching scheme according to the passenger-freight traffic ratio of the line. For example, when the passenger-freight traffic ratio is 7:3, select a combination of medium-stiffness pads and medium-strength elastic strips to achieve a balance between system performance and operation cost.
What are the detection indicators and acceptance standards for the integrated matching performance of rail fastener systems?
The detection indicators for the integrated matching performance of rail fastener systems mainly include four aspects: component matching precision, system force uniformity, vibration reduction performance and fatigue life. Component matching precision is detected by a 3D coordinate measuring instrument. The contact point deviation between the elastic strip and the rail is ≤0.5mm, the fitting rate between the pressure plate and the rail base is ≥95%, and the coaxiality deviation of the bolt is ≤0.3mm; system force uniformity is detected by strain gauges. The strain difference of each elastic strip is ≤10%, and the stress difference of each pressure plate is ≤15%; vibration reduction performance is detected by a vibration acceleration sensor. The wheel-rail impact acceleration attenuation rate is ≥60%; fatigue life is detected by bench fatigue test. The fatigue cycle number of the system under simulated load is ≥2×10⁶ times. The acceptance standards are divided according to line types: for high-speed ballastless tracks, the component matching precision deviation should be ≤0.3mm, the force uniformity difference ≤8%, the vibration reduction performance attenuation rate ≥70%, and the fatigue life ≥3×10⁶ times; for heavy-haul ballasted tracks, the component matching precision deviation should be ≤0.5mm, the force uniformity difference ≤12%, the vibration reduction performance attenuation rate ≥50%, and the fatigue life ≥1.5×10⁶ times; for ordinary-speed mixed-traffic tracks, the component matching precision deviation should be ≤0.8mm, the force uniformity difference ≤15%, the vibration reduction performance attenuation rate ≥40%, and the fatigue life ≥1×10⁶ times. During acceptance, 10 measuring points are sampled per kilometer of line, and all must meet the standards to be judged qualified.
What is the vibration and noise reduction integrated matching technology for the fastener system of urban rail transit?
Urban rail transit is close to residential areas, with extremely high requirements for vibration and noise reduction. The core of the vibration and noise reduction integrated matching technology of the fastener system is to achieve "multi-component coordinated vibration reduction + noise source control". First, adopt vibration-damping integrated components. Select double-layer composite under-rail pads. The upper layer is made of polyurethane with good vibration-damping performance, and the lower layer is made of rubber with excellent sound insulation performance. The vibration and noise reduction amount of the double-layer pad is more than 15dB higher than that of ordinary pads. Second, optimize the structural design of the elastic strip. Adopt low-stiffness elastic strips. The vertical stiffness of the elastic strip is designed to be 30kN/mm, which is 40% lower than that of traditional elastic strips, and can effectively reduce the vibration transmission caused by wheel-rail contact. At the same time, adopt elastic pressure plate design. A rubber buffer pad with a thickness of 5mm is installed between the pressure plate and the rail, which can reduce the rigid contact between the pressure plate and the rail and reduce friction noise. In addition, install a sound insulation cover at the connection between the fastener system and the sleeper. The sound insulation cover is made of aluminum alloy, filled with sound-absorbing cotton inside, which can further block the propagation of vibration and noise. During installation, ensure the accurate installation position of each vibration-damping component to avoid attenuation of vibration-damping effect caused by installation deviation. This technology can reduce the wheel-rail noise of urban rail transit to below 65dB, meeting the environmental noise standard of residential areas.