Design of a concept wedge-shaped self-levelling railway sleeper

Differential railway track settlement can result in ballast voids, leading to sleepers that hang from the rail and are no longer supported by the ballast. These hanging sleepers are damage for track component. As a solution, this paper proposes and investigates a new concept sleeper with a wedge-shaped geometry, intended to stimulate the...

Railway ballast performance: Recent advances in the understanding of geometry, distribution and degradation

Railway ballast performance is dictated by a complex mix of mechanical properties. These effect its performance at the particle level for example in terms of particle degradation, but also at the track system level in terms of settlement and stability. Therefore this paper seeks to develop new understandings of ballast behaviour and identify...

Efficiency analysis and optimisation of DEM for railway ballast track simulations: Multi-layer shape model of lateral resistance

The railway ballast layer provides the function of bearing loading, resisting geometry degradation, and drainage. In those related research, the behaviour of ballast assembly can be obtained by laboratory (or in-situ) tests. Limited simulation methods can be used to analyse the behaviour of ballast particles at the mesoscopic level. The...

Railway ballast material selection and evaluation: A review

The properties of railway ballast material are affected by the local geologies and climatic environments from which the parent rock is sourced. These factors can make it challenging to select the most appropriate material for railway applications. To address this issue, this paper first reviews the means of ballast selection in complex...

Railway ballast

Railway ballast is normally made of crushed rocks with grading (particle size distributions). Ballast is inevitably suffering from more rapid degradation. Because ballast keeps undergoing and dissipating most of the train loadings, furthermore, the train speed and freight weight are increasing, causing more intensive loadings to ballast. To...

Numerical analysis of train-track-subgrade dynamic performance with crumb rubber in ballast layer

Crumb rubber (CR) has been proposed to apply in the ballast or sub-ballast layer for ballast degradation mitigation and vibration (noise) reduction. The CR can change the ballast layer stiffness, which can affect the train-track-subgrade dynamic performance and cause travel comfort and safety issues. Towards this, this study aims at...

Review of ballast track tamping: Mechanism, challenges and solutions

Railway ballast beds bear cyclic loadings from vehicles and deteriorate due to ballast particle degradation (breakage and abrasion), ballast pockets (subgrade defects), fouling (or contamination) and plastic deformation of the beds. Ballast bed deterioration changes the ballast track geometry, which leads to uncomfortable rides, exacerbates...

Experimental and numerical study on lateral resistance of frictional sleeper with arrowhead groove

To enhance the stability of continuous welded rail (CWR) tracks, frictional sleepers have been developed. The frictional sleepers are new types of sleepers with grooves on the bottom, and different bottom grooves improve lateral resistances at different magnitudes. In this study, single sleeper push test (SSPT) and its model with discrete...

Rheology study of ballast-sleeper interaction with particle image Velocimetry (PIV) and discrete element modelling (DEM)

Ballast rheology is a phenomenon that describes movements of ballast particles due to the discrete nature, which eventually leads to the ballast bed fluid deformation after a long-time service. In most cases, ballast rheology is the main reason of track irregularity that leads to some track defects, e.g., hanging sleeper and mud spots....

Experimental and numerical study on lateral and longitudinal resistance of ballasted track with nailed sleeper

Lateral and longitudinal resistance of ballasted track are two main indicators for the track stability quantification. Aiming at improving the lateral and longitudinal resistance, nailed sleeper is studied with single sleeper push tests (SSPTs) and discrete element modelling (DEM). The SSPTs were applied to study how much resistance the...

Calibration for discrete element modelling of railway ballast: A review

The discrete element method (DEM) has been confirmed as an effective numerical method for modelling railway ballast, and successfully used to analyse a wide range of ballast-related applications (e.g. geomaterials). However, there still exists some aspects under development. Among them, the model calibration can be the most significant one ...

Discrete element modelling of rubber-protected ballast performance subjected to direct shear test and cyclic loading

The rubber-protected ballast (RPB) is made from natural ballast particles and crumb rubber particles. The crumb rubber is shredded waste tires. RPB was chosen to replace the ballast as it has higher resistance to breakage and abrasion. However, the static and dynamic performance of the RPB has not been confirmed yet. Towards this end,...

Effect of sleeper bottom texture on lateral resistance with discrete element modelling

The lateral stability of ballasted track becomes more important because of the safety requirement under the demand of higher train speed and heavier axle load. To increase the lateral resistance of ballast bed, this paper proposes three types of new sleepers, frictional sleepers. The frictional sleepers are sleepers with different shapes of...

Ballast Mechanical Performance with and without Under Sleeper Pads

With the train speed and axle load increasing, excessive stresses are produced and transmitted to the ballast layer, inducing rapid ballast degradation. To solve this issue, the under sleeper pads (USPs) have been widely applied between sleepers and ballast particles as the elastic layer. In this research, laboratory tests using half-sleeper...

Image analysis for morphology, rheology and degradation study of railway ballast: A review

The performance and deformation of ballast bed are significantly influenced by the particle morphology (size and shape), the rheology (translation and rotation), and the degradation (breakage and abrasion). Regarding the ballast particle morphology, the ballast particle size is generally measured by sieving and described with the Particle Size...

Effects of crumb rubber size and percentage on degradation reduction of railway ballast

Higher speed, more freight and frequent maintenance increase ballast degradation and reduce the ballast lifespan. To reduce ballast degradation, crumb rubber used as buffering aggregates in ballast bed is relatively unexplored and needs more studies, because using it has the advantage of reusing the waster rubber and absorbing the noises. The...

Experimental and numerical investigations on the shear behaviour of recycled railway ballast

Ballast degradation is frequently observed under cyclic loading, and results in bearing capacity and drainage problem of ballast track. To keep the stability and safety, periodical maintenances are needed, such as cleaning and replacement, which produce a huge amount of wasted ballast. Thus, reusing the deteriorated ballast can become a...

Ballast degradation: Effect of particle size and shape using Los Angeles Abrasion test and image analysis

Ballast track is the most widely used track for the railway transport, and ballast bed plays a significant role to provide resistances during train operation. Generally, the ballast bed consists of crushed stones. To achieve the mitigation of ballast degradation, the first priority is to describe the degradation development and to study its...