Enhancing Rail Track Performance Using Recycled Rubber Energy-Absorbing Grids: Laboratory and Field Evidence

Abstract

Rail tracks deteriorate over time due to dynamic wheel loads, a process that necessitates frequent and costly maintenance. This paper presents the results of laboratory and field tests on the application of a recycled rubber energy-absorbing grid (REAG), made from conveyor belts previously used in mining to enhance the performance of ballasted tracks. These rubber grids having square apertures made with a waterjet cutting technique were evaluated under simulated cyclic loads from heavy, high-speed trains using a large-scale process simulation testing apparatus (PSTA). The laboratory data indicate that REAG significantly improves track performance by providing substantial energy absorption and enhanced particle interlocking. The test data also show that REAGs reduce lateral displacement, settlement, and ballast breakage, as well as enhance the resilient track modulus (MRT) and energy dissipation per load cycle (Ed) of the track. Empirical models were then developed and calibrated with the laboratory results to predict the MRT and cumulative energy dissipation after 250,000 cycles considering the role of REAG under cyclic loading. To validate the effectiveness of REAG in real-world conditions, a fully instrumented track section was constructed at Chullora, New South Wales, Australia. Field testing demonstrated that REAG placed underneath the ballast layer reduced settlement (by 18.3%) and vertical stress (up to 27%) in the sleeper-ballast and ballast-capping interfaces, as well as the acceleration measured on the sleepers, providing a promising solution to reduce the noise and vibration of railway tracks.