Risk management through systems assurance

To show that systems are acceptably safe for deployment into an operational railway, a program of systems assurance is necessary. What is acceptably safe is dependent on the risks associated with system operation. As such, a supplier's systems assurance program must evolve in response to the railway authority's risk management requirements. The basis for expression of a railway authority's risk requirements has typically been a set of risk tables. These tables provide a mechanism for classifying: (i) accident severity; (ii) accident frequency; (iii) risk; and, (iv) risk tolerability. To achieve risk reduction, there has been a growing reliance on the use of Safety Integrity Levels (SILs). This paper discusses our experiences' in developing an integrated systems assurance program, in response to the risk management requirements of our customer base. We consider the risk tables that form the basis for risk classification and risk tolerability, and recount from our experience cases where risk tables and rules about safety integrity level allocation have led to anomalous results. In relation to SIL allocation, the problem of commercial-off-the-shelf (COTS) software is specifically noted. As a way forward, we suggest that more detailed risk models should be developed and maintained by rail authorities, with the suppliers of safety-related systems being asked to contribute to and support those models.

Media Info

  • Pagination: 9p. ; PDF
  • Monograph Title: Railway technology for the 21st century: CORE 2000: conference on railway engineering, May 21-23 2000, Glenelg, South Australia

Subject/Index Terms

Filing Info

  • Accession Number: 01532104
  • Record Type: Publication
  • Source Agency: ARRB
  • Files: ATRI
  • Created Date: Jul 29 2014 11:55AM