Matching the Static Stiffness of Rail Pads with Track Smoothness
What problems are caused by too high pad stiffness?
High stiffness reduces elasticity and increases wheel-rail impact. Vibration and noise rise, lowering comfort. Rails, bolts and sleepers suffer higher stress and shorter fatigue life. It easily causes corrugation and vibration defects, especially on high-speed lines.
Why is low stiffness also harmful?
Low stiffness causes excessive rail deflection and poor geometry retention. Gauge and level change frequently. Large deformation accelerates creep and permanent set. Elasticity declines over time, worsening smoothness. Lower stiffness does not mean better comfort.
What is the stiffness difference between high-speed and ordinary lines?
High-speed lines use narrow, moderate stiffness for high smoothness. Ordinary lines allow a wider range for economy. High-speed lines often use polyurethane pads; ordinary lines use rubber pads.
How does uneven stiffness affect the track?
Uneven stiffness creates hard and soft spots, causing periodic impact. It induces corrugation, loose fasteners and sleeper damage. Vibration and noise increase, reducing ride quality. It accelerates track deformation and maintenance.
How to judge stiffness suitability on site?
Uniform rail deflection without bouncing indicates good stiffness. Excessive compression, cracking or extrusion shows too low stiffness or aging. Abnormal vibration or noise suggests high stiffness. Combine with component damage for comprehensive judgment.