SPAD events: an investigation of human and organisational factors and the underlying stakeholder perspective

The railway industry is a complex system with a continuously changing environment. Within 2018, passenger trains covered 520 billion kilometres carrying 1700 million passengers. During the period 1994-2007 there were seven fatal accidents on the UK railway network, four of which were Signals Passed at Danger (SPAD) events. These were Cowden in 1994, Watford Junction in 1996; Southall in 1997 and Ladbroke Grove in 1999. SPAD events vary in severity and whilst most are not fatal there is the potential to cause serious injuries to passengers and train staff and damage to railway infrastructure. The rapid technological advances due to these fatal incidents of the late 1990’s has seen an improvement in safety systems; however, these changes have had a limited impact on the occurrence of SPAD events. The number of SPAD events has fluctuated since 2003-04 with an average of 307 SPAD events occurring each year. Between 2017 and 2018, a SPAD occurred on average 5-6 times each week, totalling 295 SPADs in the year. Whilst the developments in safety systems and infrastructure has caused a decline in fatalities of both passengers and workforce each SPAD event has the potential to be catastrophic. Therefore, the aim of this thesis was to investigate human and organisational factors contributing to SPAD events and to explore the underlying stakeholder perceptive of the barriers to learning from SPAD events to identify why SPADs are continuing to be a near daily occurrence on the UK railway network.