The high demands of the modern railway system require – either in urban tramway transport systems, or in mixed traffic transport – the use of track components with correspondingly high resistance against rail degradation to cope with higher loads, more passengers and shorter train intervals.
Based on the knowledge about the positive effect of fully pearlitic material concepts with C > 0.9% on the performance of rails, a new class of rail steels was introduced in tracks more than 20 years ago; the so-called Super Premium Rail Steels. Based on this great deal of theoretical and practical experience, the success story of rail steels with higher carbon content has been transferred from heavy-haul application into mixed traffic and urban railways. The very positive behaviour of these Super Premium Rails does not only involve rail wear minimization, but also the behaviour of the rails with respect to the formation of corrugation and the development of rolling contact fatigue (RCF) is extraordinarily improved. The paper deals with track experiences and the most economic rail grade strategy for mixed traffic as well as urban transport.
However, a holistic system approach requires consideration and optimization of both sides of the wheel/rail contact. It is a common perception that reducing the wear rate of the material on one side of the wheel/rail interface will result in an increase in wear on the other side of the interface. Within the paper a review of research and published papers has been undertaken and it has been found that increasing the hardness of one material has little or no effect on the wear rate of the other material, and many researcher have actually observed a reduction in the wear rate in both materials when the hardness of one of them is increased. Highly resistant materials can therefore be beneficial for rail as well as the wheel and provide a benefit in reducing whole system maintenance costs.

Rail, Maintenance, Wear, RCF