Nonlinear modelling and analysis of moving train loads on interspersed railway tracks

The interspersed pattern sleeper of railway track, which is a replacement of old timber sleeper with concrete, is often used as a temporary maintenance for second or third class railway lines with aging timber sleepers. However, their negative effect on the railway has to be taken into an account. The numerical simulations of interspersed sleeper railway tracks are conducted as well as the plain ones using a finite element program, STRAND7, so that the precise numerical models can be established. Two moving point loads, 100 kN each, are simulated to represent a passenger train bogie moving along each rail in 2 dimensional plane. Dynamic displacements and accelerations of all sleepers are then evaluated. Sensitivity analyses are carried out by varying the speed of the moving train loads from 5 km/h to 120 km/h and by changing the type of the interspersed patterns to determine the dynamic behaviours that can cause any more rapid deterioration of the interspersed tracks compared with plain railway tracks. The results demonstrate the potential sources of structural vibrations that will swiftly degrade the interspersed railway tracks. The insight will help track engineers to plan predictive maintenance and inspection of the interspersed railway tracks in live operational networks.