On best practices for trackbed design

This paper reviews the best practices of trackbed design for railway projects. Various existing methods have been studied and recommendations for more economical design are provided. The analytical/empirical methods from various standards such as UIC, AREMA, British Rail, and Australian standards, as well as other commonly used methods such as Raymond and Li-Selig are compared based on a typical track embankment cross section. The outcome was then evaluated against 2D and 3D numerical models. Incorporating numerical methods is shown to render considerable reductions in the required prepared subgrade/structural fill materials and allow for assessment of long-term design issues, such as subgrade shear failure due to excessive plastic deformations.