Railway Track Subgrade Failure Mechanisms Using a Fault Chart Approach

Railway track subgrade failure induced by climate related softening, may lead to unplanned maintenance costs and consequential and costly train delays. The softening process can be due to the presence of water in the upper parts of the track foundation due to inadequate drainage system or poorly maintained railway track drainage. In order to better make use of scarce resources and plan railway track and associated drainage maintenance rationally it would be helpful to better understand and quantify the relationships between the causes of poor subgrade and the railway track drainage system. The understanding of railway track drainage associated failure can be further used to infer engineering knowledge into railway performance models and associated risk analysis methodologies. To this end, this paper describes the development of a fault tree analysis approach which considers the failure mode(s) for railway track subgrade. The fault chart has been developed in two stages, in the first stage, failure mechanisms are diagnosed utilizing a cause-effect diagram, and in the second stage a fault tree analysis (FTA) is performed.