Classification and technical characteristics of modern fastener systems
Current mainstream fasteners can be divided into three categories: rigid, semi-elastic and fully elastic. Rigid fasteners such as DTVI2 are mostly used in subway tunnel sections. Their cast iron base is directly bolted to the concrete sleeper. They lack vertical elasticity but have excellent lateral stability. Semi-elastic fasteners are represented by the WJ-8 type commonly used in high-speed rails. Through the combination of microporous rubber pads under the rails and elastic pads under the iron pads, a system stiffness of 60-120kN/mm is achieved, meeting the dynamic requirements of trains with a speed of 350 kilometers per hour.
Fully elastic fasteners such as the Köln Egg type use vulcanized rubber to completely wrap metal parts. The system stiffness can be as low as 20kN/mm, and are widely used in vibration and noise reduction sections of urban rail transit.
Insulation performance has become an important indicator of modern fasteners. The GF-2 fasteners used in Guangzhou Metro Line 18 use glass fiber reinforced nylon insulation blocks with an insulation resistance of more than 10^9Ω at a voltage of 1kV, effectively preventing stray current corrosion.
In terms of temperature adaptability, the cold-resistant fasteners used in the Harbin-Dalian high-speed railway still maintain the stability of the elastic modulus at -40°C, and the risk of low-temperature embrittlement is reduced by 80% compared with conventional products.
The development history of rail fasteners is essentially an evolutionary history of railway safety and comfort.
From millimeter-level dimensional accuracy to megapascal-level stress control, these "metal skeletons" hidden under the rails are using the power of technology to support a faster and smoother new era of rail transportation.
With the deep integration of intelligent materials and digital twin technology, future rail fasteners may have self-diagnosis and self-adjustment functions, providing a more solid technical foundation for the construction of a strong transportation country.
