ABSTRACT
This chapter describes a method that was commissioned by Network Rail and used on major projects to meet the safety risk assessment requirements associated with trains overrunning signals. The method is called overrun risk assessment method (ORAM) and uses structured expert judgement within a workshop setting. The chapter explains how ORAM was developed to support the end users in making structured expert judgements on the human factors issues associated with signals passed at danger. The causal factors leading to a driver disregarding a signal can be subdivided into those that primarily affect perception of signal and those that primarily affect decision and response selection. The engineered aspects of the railway primarily determine the factors that affect a driver's ability to stop a train at a danger signal. Qualitative estimate of the overrun risk at a particular signal is made at the risk assessment workshop by selecting ranking for each component of ORAM.
