Safety-pre-requisite or just another business issue?

This paper outlines developments in the application of Quantified Risk Assessment to railway systems and specifically illustrates their use in the appraisal of signalling systems by reference to case studies. The paper shows how such techniques are being used to estimate change in safety performance provided by renewals and how benefits may be integrated with capital and operating cost parameters to estimate ´value for money´. The paper also outlines limitations of the techniques with reference to case studies