Risk and Safety in Engineering Processes

Abstract

This research project focused on the treatment of safety risks in railways. Existing methodologies for assessment and management of the safety risk on railways are mostly empirical and have been developed out of a need to satisfy the regulatory requirements and in response to a number of major accidents. Almost all of these processes and methodologies have been developed in support of approvals of specific products or very simple systems and do not add up to a holistic coherent methodology suited for analysis of modern, complex systems, involving many vastly different constituents (software, hardware, people, products developed in different parts of the world, etc.). The complexities of modern railway projects necessitate a new approach to risk analysis and management. At the outset, the focus of the research was on the organisation of the family of existing system analysis methodologies into a coherent, heterogeneous methodology. An extensive review of existing methodologies and processes was undertaken and is summarised in this thesis. Relationships between different methodologies and their properties were investigated seeking to define the rules for embedding these into a hierarchical nest and relating their emergent properties. Four projects were utilised as case studies for the evaluation of existing methodologies and processes and initial development. This thesis describes the methodology adopted in support of development of the System Safety Case and the structure of the document. Based on that experience and knowledge a set of high level requirements was identified for an integrated, holistic system safety analysis and management process. A framework consisting of existing and novel methodologies and processes was developed and trialled on a real life project. During the trial several gaps in the process were identified and adequate new methodologies or processes defined and implemented to complete the framework. The trial was very successful and the new framework, referred to as the Engineering Safety Case Management Process is implemented across the London Underground Upgrades Directory