Development of integrated railway ballast quality index.

The quality of ballast materials is an important criterion in railway track maintenance management systems. Although various studies have been made on the characteristics of ballast aggregates and ballast mechanical behaviours, making an optimal decision on the selection of appropriate ballast materials is still a serious challenge in the railway industry. It indicates a need for an integrated ballast quality index which could help to ensure improved cost-effectiveness of track maintenance. In response to this need, the mechanical, physical and environmental properties of the ballast were categorised and weighted based on their level of influences on the ballast overall conditions. Consequently, a ballast quality/condition index was developed as a function of the influencing parameters. To examine the practicability and applicability of the developed method/index, three types of ballast materials were taken from different sources and their quality was evaluated and discussed using the new index. Through illustrating the effectiveness of the new index in evaluation of ballast materials, it was shown that the new index can play a role to allocate an optimal ballast material quality and improve cost-effectiveness of the current maintenance by providing the ability to optimise ballast maintenance planning. [ABSTRACT FROM AUTHOR]