Publication Details

Indraratna, B., Nimbalkar, S. & Rujikiatkamjorn, C. (2013). Modernisation of rail tracks for higher speeds and greater freight. The International Journal of Railway Technology, 2 (3), 1-20.


An efficient transportation infrastructure has become utmost priority for global economic reforms. Railways are designed to provide high speed passenger and heavy haul freight transportation. Ballast is one of important constituents of the rail track however, it experiences excessive deformation and degradation from trains operating at high speeds. In addition, tracks built along coastal areas often undergo large settlements due to soft compressible clay deposits. This leads to progressive track deterioration and necessitates frequent and costly track maintenance. The use of artificial inclusions such as geogrids, geocomposites, shock mats and prefabricated vertical drains (PVDs) is often an attractive design alternative for track practitioners. However performances of these inclusions are predominantly governed by their technical specifications in addition to geotechnical characterization of the track substructure including ballast and subgrade. Therefore, full scale field trials were conducted on instrumented track sections built along the south-east coast of Australia (e.g. Bulli and Singleton). The performance of geogrids and geocomposite was demonstrated in terms of specific key parameters such as stiffness and aperture size of geogrids, placement location of geogrids, as well as subgrade types. Placement of shock mats (rubber pads) in rail tracks has also lead to the mitigation of particle breakage. Empirical approaches to relate ballast strains with the number of load cycles are presented. Bearing capacity analyses of track substructure is discussed. The use of PVDs to dissipate the excess pore pressure for increased stability of the soft clay subgrade is presented.

Link to publisher version (URL)

The International Journal of Railway Technology