Accident Modelling of Railway Safety Occurrences: The Safety and Failure Event Network (SAFE-Net) Method

Abstract

The Safety and Failure Event Network (SAFE-NET) method of accident modelling has been developed as part of a human factors research project which aimed to identify the relationships of contributing factors (including human factors) to major railway safety occurrences for the Rail Safety Regulator in Queensland, Australia. Whilst accident modelling had certainly progressed through various reiterations since the first simple linear model was developed, the identified gap has been for a practical methodology for undertaking accident modelling which can now cope with modern day system complexity and truly reflect the socio-technical systems under review. The aim of this research was to identify the contributing factors to railway safety occurrences and to examine how contributing factors were interconnected and networked. To meet this aim major railway safety occurrence reports which were submitted to the Rail Safety Regular, for a five year period (2006 – 2010), were analysed and data was collected on the contributing factors using the Contributing Factors Framework (CFF), a human factors tool developed for the rail industry in Australia. The contributing factors for various types of safety occurrences were then modelled using the Safety and Failure Event Network (SAFE-Net) method. The results have enabled various types of railway safety occurrences to be modelled with a view to understanding how the contributing factors are interconnected and which factors are the main contributors to various types of safety occurrences. This representation allows management and others to review the railway system elements at a deeper level and enable the focus of safety efforts to be directed to the most important and central elements from a systems perspective.