ABSTRACT
The rail track network forms an important part of the transportation infrastructure in Australia. Salim showed that Australia has more than 43,000 km of narrow, broad, standard and dual gauge ballasted rail tracks. The ballast layer plays a crucial part in transmitting and distributing the wheel load from sleepers to the underlying sub-ballast and subgrade at a reduced and acceptable stress level. The main input parameters considered in track design include: dynamic wheel loads, tonnage by million gross tonnes, moduli of granular materials and subgrade soil, subgrade soil type and compressive strength. The properties of the sub-ballast and subgrade formation soils are needed to enter into the program prior to the design process. Geosynthetics have been widely used in track construction and rehabilitation worldwide over decades. The application of geosynthetics for improving ballasted rail tracks has proved to be a cost effective way of reducing the lateral movement of ballast particles and of further reducing any permanent deformation.
