Experimental and numerical research on the failure of railway vehicles coupling links

Abstract Two modes of failure are analysed for coupling links, the mechanical connections that transmit traction forces between vehicles along the length of a train. Coupling links are designed to withstand the dynamic loads in normal operation but may break if applied loads exceed safe operating limits. Fractography of two failed links revealed that one had failed through brittle fracture, and one through ductile fracture. Metallography indicated that one sample was hardened and tempered with typical tempered martensite microstructure and the other was normalized with a ferrite-pearlite microstructure. A numerical model of a coupling link is developed and validated against experimental data. Results indicate that the failed links experienced loads above the permitted limit.