ABSTRACT
During the design of modern railway tracks it should be taken into account that the continuous increase in train speed leads to increase in dynamic loads transmitted to the track as well as higher quality and resistant requirements are expected for track section. These considerations make essential the inclusion of modifications in track components in order to optimize its mechanical behavior with the aim of extending its life while service and maintenance costs are reduced. However, this designing task should be undertaken carefully since the use of different configurations of track section can lead to important changes in fundamental parameters (such as track stiffness, settlement and loads damping) depending on the characteristics of the components, which requires the understanding of its influence. Thus, this paper analyses the mechanical performance of a number of different track sections reproduced in laboratory, assessing the effect of the characteristics of the main components to be optimized such as elastic elements (with different stiffness), ballast and types of sub-ballast (with diverse bearing capacity). Results show that changes in track response are significantly lower than those observed in the properties of the components, particularly in the case of components over the ballast layer whose effect is lower than those under such layer (by, for example, adding elastic mats). Moreover, it was seen that reduction in track stiffness by modifying components over the ballast allows for better track behaviour than in the case of reducing the stiffness of components under ballast.
