Optimising the track bedding stiffness and settlement behaviour at insulated rail joints

Besides turnouts, insulated rail joints are the most frequent cause of track failure. They disturb track homogeneity and cause a local variation in track bedding stiffness, leading to an increase in dynamic loading. Local variations in track bedding stiffness due to turnouts, insulated rail joints, as well as other necessary devices in the track, lead to an increase in maintenance demand and inherent costs. By implementing under-sleeper pads, the track bedding stiffness and settlement behaviour at insulated rail joints can be optimised, which has been confirmed by measurements conducted in the USA and China.
Insulated rail joints with an optimised track stiffness yield promising maintenance-related and economic benefits, as also alluded to in this article.