Advanced approach for assessing the degradation of railway ballast particles through detailed 3D scanning

Abstract

The degradation of the ballast bed used in railway infrastructure is a significant safety concern requiring proper monitoring and preventive maintenance. Currently there is no universally accepted international standard specifying degradation resistance conditions in ballast, necessitating innovative parameters and methodologies for analysis. This study aims to quantify the degree of degradation of ballast and aid in the decision process to replace the ballast bed, based on a detailed 3D scan of the ballast samples. Thirty ballast specimens were scanned and studied, corresponding to three groups: fresh crushed ballast, specimens that have been used in track, and specimens that have been heavy artificially altered using a degradation test. A new analysis methodology was developed, which hinges on the angle formed by the normal vector of each facet of the scanned specimen and the normal vectors of its contiguous facets. The effects of different regularisation sizes and the repeatability of this methodology and the distribution of angles within the facets of the specimen were analysed. The proposed methodology quantifies the degree of degradation in ballast specimens and effectively differentiate between freshly crushed specimens and those used on tracks, regardless of the specimen's size or morphology, offering potential for large-scale maintenance applications in track environments.