Engineering researchers discover technique to improve railway safety

Engineering researchers at the University of Wollongong have discovered an innovative way of stabilising railway tracks to cater for modern high-speed trains that carry heavy loads.

Research students working under the guidance of Professor Buddhima Indraratna, of UOW's Department of Civil, Mining and Environmental Engineering, have found that inserting plastic (polymer) grids underneath ballast and the placing of a synthetic fabric to separate the foundation soil from the overlying rock particles can make the railway tracks withstand much higher dynamic loads imposed by the passage of fast trains.

Professor Indraratna said that the flexible but strong polymer grids when placed within the ballast bed would introduce internal resistance against the ballast particles wanting to move horizontally against each other during the passage of trains — thereby reducing the risk of fracturing of particles.

At the same time, the synthetic geo-fabrics will prevent the upward movement of foundation soils into the voids of the ballast bed making the ballast particles lose friction as well as blocking drainage during wet weather, he said. "The result is a novel rail track in which natural geological materials are blended with synthetics to give a stronger composite with greater load bearing capacity and reduced settlement," according to Professor Indraratna. The rail track research has been undertaken within the Cooperative Research Centre for Railway Engineering and Technologies, funded by the Federal Government,where close to $1 million a year is received in research grants. The funding has enabled the design and construction of several items of unique, large-scale testing equipment to simulate the conditions that occur in rail trucks.

Professor Indraratna said the research findings based on these test rigs was certain to lead to Australian railway authorities modernising the old-fashioned tracks. He said Australian geosynthetic companies were extremely excited because of the huge potential for using their polymer products in national railway tracks that are among the longest in the world. In NSW alone, more than $12 million is spent annually on replacing the crushed ballast on rail tracks over regular track maintenance periods.