Building better rail tracks

Impact: Using geosynthetics to improve the resilience of Australian railways

Rail transport is an inherent component underpinning the Australian economy, in particular through the transport of natural resources such as coal and iron ore to port.

Yet some ballasted rail tracks in many parts of the country lack the capacity to support the increasingly heavier and faster trains associated with industry.

The ballast underpinning tracks is subject to degradation and the infiltration of fine particles, such as coal dust, and soft subgrade soils contaminating the overlying ballast decrease its porosity, impeding drainage. These issues lead to excessive track settlements and instability, as well as high maintenance costs.

Professor Buddhima Indraratna and his team are investigating solutions to mitigate these problems by utilising geosynthetics such as polymer geogrids, geocomposite, geocells and rubber mats, through the ARC Centre of Excellence in Geotechnical Science and Engineering.

This project examines the fundamental mechanisms of geosynthetics-reinforced ballast using a unique large-scale, track process simulation apparatus, in conjunction with novel computational approach based on Discrete Element Modelling and Finite Element Modelling.

The computational models are calibrated and validated using actual field measurements and modern instrumentation including digital extensometers, settlement pegs, pressure cells, accelerometers and Fiber Bragg Grating optical sensors.

Already, a considerable portion of the R&D work in this area of research is captured by UOW-developed computer software, SMART– Systematic Methods of Analysis of Rail Track, which is capable of accommodating a variety of problematic ground conditions in Australia in user-friendly modules. It has shown that the cost of geosynthetics will only be a small fraction of the actual savings gained by extending the track maintenance cycle and reusing the discarded aggregates improved by geosynthetics.