A comparison of railway track foundation design methods

One of the primary functions of the layers that make up the trackbed in a conventional railway track system is to distribute wheel/rail contact forces so that the stresses in the subgrade are of an acceptable level. To ensure that the trackbed layers perform this task adequately, there are a number of design procedures that may be used to calculate an appropriate thickness of the layers. This paper describes and compares five such design procedures from the USA, UK, Europe, and Japan. The comparisons show that the design procedures give large differences in the calculated layer thicknesses which are due to the design methodologies used in each procedure. Consequently, to enable an appropriate design procedure to be adopted for a given set of conditions, it is necessary to have a thorough knowledge of the methodologies employed together with their inherent assumptions.