Torque Management of Fastening Systems and Prevention of Rail Longitudinal Creep
Q1: What core contents does the torque management of the fastening system include?
A1: The torque management of the fastening system covers the initial installation torque setting, on-site retightening torque standard, torque detection cycle and method of accessories such as elastic bars, bolts and pressing plates, as well as the judgment standard and treatment plan for torque abnormality. It covers the whole process of design, construction and operation and maintenance to ensure that the torque of the fastening system always meets the design requirements.
Q2: Why is insufficient torque the main cause of longitudinal rail crawling?
A2: Insufficient torque will reduce the bonding force between the fastening system, rails and sleepers, and cannot effectively restrict the longitudinal displacement of rails; the traction force, braking force and rail temperature force generated by train operation will push the rails to crawl slowly, which will cause uneven rail gaps and joint misalignment after long-term accumulation, seriously damaging the longitudinal stability of the track.
Q3: What damage will excessive torque cause to the fastening system and rails?
A3: Excessive torque will cause plastic deformation of accessories such as bolts and elastic bars, lose elasticity and fastening ability, and even fracture; at the same time, it will bring additional longitudinal stress to the rails, causing rail bending and deformation, and under-rail pads are damaged under pressure, which not only damages accessories, but also affects the normal service performance of rails.
Q4: What impacts will longitudinal rail crawling have on under-rail pads and spikes?
A4: Rail crawling will drive the displacement of under-rail pads, leading to aggravated eccentric pressure and wear of pads and reduced vibration reduction performance; spikes will bear shear force due to rail displacement, resulting in loosening, fracture and anchoring failure, and the fixed structure of the track is damaged, further aggravating crawling and forming a vicious circle.
Q5: How to comprehensively prevent and control longitudinal rail crawling combined with torque management?
A5: Strictly set the torque of the fastening system according to the design standards, and use torque wrenches for construction and detection; increase the frequency of torque detection in sections prone to crawling such as curves and slopes, and retighten accessories with abnormal torque in time; install anti-crawling devices and select under-rail pads with high friction coefficient; establish a rail crawling monitoring account and dynamically adjust control measures.