Overall Longitudinal Resistance of Fastening System and Rail Creep Prevention
Q1: What are the main components of the fastener longitudinal resistance?
A1: It is mainly composed of friction resistance generated by clip clamping force, rail base-pad friction force, and gauge block-shoulder lateral resistance, among which clip friction resistance accounts for the largest proportion.
Q2: Why does insufficient longitudinal resistance cause rail crawling?
A2: When the longitudinal force generated by train braking, traction and temperature force exceeds the fastener resistance, the rail will move directionally to form crawling, which will lead to abnormal rail gaps and joint diseases.
Q3: What factors will cause the attenuation of fastener longitudinal resistance?
A3: Clip torque drop, pad aging creep, rail base pollution and slippage, gauge block wear, bolt loosening, etc., will all cause the resistance to gradually decrease.
Q4: What damage does rail crawling cause to joint smoothness?
A4: Crawling causes uneven rail gaps, some rail gaps are closed and some are enlarged, joints have steps and collapses, impact increases, and fishplates and bolts are accelerated to damage.
Q5: How to stably maintain fastener longitudinal resistance?
A5: Regularly retighten clip torque; replace aging pads; keep rail base clean; adopt pads with high friction coefficient; add anti-crawlers when necessary.