Innovative passive yaw damper to increase the stability and curve-taking performance of high-speed railway vehicles

Yaw dampers are implemented on high-speed trains to reduce their tendency towards unstable movement (hunting) while running at high-speed. Although they have a positive influence on the vehicle's stability, these devices impose a steering resistance action on the bogies while negotiating tight curves at low speed, and so standard passive devices must be designed taking conflicting objective functions into account. This paper presents an innovative yaw damper able to overcome this trade-off by introducing a passive solution able to modify this component's working behaviour during different vehicle operating conditions. To quantify the efficacy of this solution, numerical models of innovative and standard dampers were developed and validated by means of experimental tests. Then, they were co-simulated with a multibody model of a real test case vehicle running under different operating conditions.