Contents 3 Contents Preface.................................................................................................................15 1 Basic Characteristics of Railway Systems and the Requirements for Signalling............................................................................17 1.1 Introduction...........................................................................................................17 1.2 Specific of Railway Systems ................................................................................17 1.3 Railway Signalling and Control ............................................................................18 1.3.1 Definitions...............................................................................................................18 1.3.2 The Safety-related Railway Theory ..........................................................................18 1.3.3 Functional Structure................................................................................................21 2 Safety and Reliability in Signalling Systems................................................24 2.1 Safety Basics ........................................................................................................24 2.1.1 What is RAMS(S)? ..................................................................................................24 2.1.2 Safety/Security .......................................................................................................24 2.1.3 Availability, Reliability and Maintainability..................................................................25 2.1.4 Role of the RAMS Components in the Railway System ...........................................26 2.2 Safety Principles in Railway Operation................................................................27 2.2.1 Dealing with Errors, Failures and Disturbances (E/F/D) ............................................27 2.2.2 Analysis of Errors, Failures and Disturbances (E/F/D) by System States ..................29 2.3 Conception of Safety and Reliability of Railway Signalling Equipment .............30 2.4 Characteristics of Reliability and Safety..............................................................31 2.5 Evaluation of Safety Level of Signalling Equipment ...........................................32 2.6 Rating of Safety Parameters ................................................................................35 2.7 Calculations of the Safety Parameters ................................................................36 2.8 Methodology of Safety Case for Railway Signalling Equipment ........................38
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