Effect of Sleeper Interventions on Railway Track Performance

Abstract

The sleeper / ballast interface is an essential stage in the transfer of train loads from a railway track structure into the ground. Generally, only a small number of ballast grains support the sleeper base. The resulting localised contact stresses can be very high, especially for modern concrete sleepers on hard igneous ballast. This may result in damage to both sleepers and ballast, and reduce the stability of the interface. The paper presents results from cyclic loading tests carried out to explore the potential for performance improvement through the adoption of different sleeper types and modifications to the sleeper / ballast interface. Measurements of resilient performance, plastic settlement, sleeper / ballast contact number and area, shoulder movement, ballast breakage and attrition and the development of ballast longitudinal pressure are used to explore and explain the effect of each intervention. It is shown that twin-block sleeper types and under sleeper pads (USP) have the potential to reduce maintenance requirements and whole life costs.

The influence of variation in track level and support system stiffness over longer lengths of track for track performance and vehicle track interaction

“…The data shown in Figure 8 are system values seen at the rail, and include the effect of the railpads. For the railpads present, the data shown indicate a trackbed stiffness of 70-90 MN/m per sleeper end, which is consistent with the sub 1 mm sleeper movements measured and would be considered to represent well supported track [63][64][65][66]. shows histograms for sleeper deflection and support system modulus for the Javelin data from Figures 7 and 8.…”

Discrete Element Modelling of Rubber-Protected Ballast Performance Subjected to Direct Shear Test and Cyclic Loading

“…This is due to the fact that the CR can induce insufficiently soft contacts between the sleeper and RPB particles, which has been proved in [54], where the soft contacts led to higher sleeper accelerations. However, in some earlier studies on the under sleeper pads (USPs) [21,22,55], they argued that the soft contacts can provide a better ballast bed performance by reducing the ballast degradation. Particularly, the difference between the USPs and RPB is that the USPs attach to the sleeper bottom without any movement and the ballast particles' rearrangement is slow, whereas RPB particles can move randomly after applied loadings and the interaction between particles is not strong enough to restrict RPB particles.…”

Numerical Modelling of Track Behavior Capturing Particle Breakage under Dynamic Loading

“…However, there are many factors and variables including loading and boundary conditions that are often difficult to control in the field (Powrie et al 2007). Therefore, large-scale laboratory tests simulating as accurately as possible the field loading and boundary conditions are pertinent to obtain realistic ballast stress-strain (deformation) and degradation behavior of rail ballast (Abadi et al 2019, Jayasuriya et al 2019.…”