Fault tree for poor drainage mechanisms of railway balalsted track

Poor railway track subsurface or surface drainage caused by the inappropriate design of drainage assets or their lack of maintenance is a major contributor to a variety of railway substructure failures and can necessitate significant unplanned maintenance and the imposition of costly speed restrictions. In order to predict and prevent the premature failure of drainage systems, track engineers need to understand the causal factors affecting poor drainage. However, this is often a difficult task due to the complex interaction between subsurface and surface drainage systems and the various poorly recognised and understood manifestations of inadequate drainage, by which the track drainage managers usually diagnose the causes of track failure and prescribes the required maintenance. To address this, this paper explores the use of fault trees to understand the causal factors affecting poor railway track drainage. A methodology is described which can be used by track drainage managers to systematically diagnose the causal factors and modes of railway track drainage failure. To this end, two sub-fault trees for subsurface drainage and three sub-fault tree for surface drainage are developed, and the applicability of the methodology is demonstrataed for the UK railway.