Risk analysis using likelihood or probability and consequence (L x C) is prone to both methodological and application errors. This contributes to difficulties in achieving risk reduction. As an alternative to the L x C model, this study reviews risk and control effectiveness within the Australian extractive minerals industry. It draws on existing models, locally and internationally, and their application in other industry contexts. The study contends that control effectiveness is more useful and beneficial than L x C alone in determining ‘acceptable’ risk. This hypothesis is substantiated by the development of an alternative model, Major Accident Control Analysis (MACA), based around the prevention of fatalities by exploring and quantifying the following control parameters: 1) controls pre and/or post event, 2) the control type, and 3) the effectiveness of the specific control. By assigning these control parameters, discrete values, comparisons between individual ‘risk’ scenarios and established numerical acceptability risk criteria are possible. The theoretical proposition of this research was tested using detailed case studies to highlight the flaws of conventional risk analysis and, instead, accentuate control effectiveness as a superior method for prioritising risk and determine acceptability. The results of the research demonstrate that control effectiveness, utilised by the MACA method, is particularly valuable when limited data is available to permit quantification, data is too generalised for the operating conditions and where qualitative risk estimates are insufficient and inappropriate to prevent fatalities. MACA employs mathematically valid algorithms previously not envisaged nor developed by earlier methodologies. Importantly, these algorithms enable an interchangeable conversion of control effectiveness ‘values’ to risk ‘values’. Beyond the immediate findings of the research, the additional benefits of control effectiveness are multiple. The principles are suitable to the dynamic nature of the minerals industry, yet are highly adaptable and can be readily applied beyond the field of mining. The methodology could be applied to any circumstance where traditional risk analysis is typically undertaken, thus demonstrating broader application and significance. Furthermore, the methodology is compatible with, and complementary to, existing risk approaches. The intrinsic flexibility offered by this alternative method makes provision for international variations of risk criteria used to determine ‘acceptability’. It is thus determined that the application of control effectiveness estimation offers benefits over and beyond those currently employed.

Construction is one of the oldest of industries in the world, with the first establishedconstruction company being established around 230 BC. One of the biggest industries inEurope, at an estimated €900 billion a year, it also accounts for 40% of total energy consumption and 40% of total waste generation in the EU1 . Although the majority ofthese are from the use phase of the built environment, there is a lack of a comprehensiveenvironmental risk management system for the construction phase. This study proposesan environmental risk management framework based on the Beer-Ziolkowski model of risk management for both site specific and non-site specific construction operations witha stakeholder centric approach. It proposes stakeholder involvement to identify the risksaided with trend analysis of strategic regulatory implications from the concernedauthority - Norwegian Ministry of Local Government and Regional Development and thecurrent orgnisational practice of objective environmental risk identification from ISO14001 guidance. Scope of site specific and non-site specific risks are narrowed down tosite operational setup and construction materials respectively, consistent with theorganisations view of the most important risks from those two classes of risks. Riskassessment is suggested through Fault Tree Analysis (FTA) method for site specific risksand European Union System for the Evaluation of Substances (EUSES) for non-sitespecific risks. Total Cost Accounting (TCA) of project alternative evaluation isrecommended with a view to internalise the external costs. A two tiered integration ofrisk information in the buisess process is suggested – categorised risk reduction processat the level of projects and general good practice aided with risk information at the policylevel. Being a framework for management of environmental risk as opposed to a methodfor a specific environmental risk, the principles and suggestions are broadly scoped withcase studies for identification and analysis of risks.Through the practice of prudent engagement of stakeholders and scientific risk assessments, this framework would help the organisation enable safer operational practices in the context of environmental effects. In foresight this in turn will have rendered the host firm more competent in terms of making sustainable business decisions. / Byggindustrin är en av de äldsta industrierna i världen. Det första företaget etabeleradesca 230 BC. Byggindustrin är även en av de största industrierna i Europa med €900miljarder i omsättning varje år, men ansvarar även för ungefar 40% av energiförbrukningen och 40% utav den totalla avfallsgeneringen i EU1. Trots att det mesta av dessa miljöfarliga aspekter kommer ifrån användningsphasen av den byggdamiljön, finns det en brist på omfattande hanteringssystem för miljörisker vid uppbyggnadsphasen. Denna studie föreslår en hanteringsmodell, baserad på Beer-Ziolkowski-modellen för riskhantering, som innehåller både byggplats baserade och icke byggplatsbaserade risker med en centrerad orientering vid just aktieägare samt andraberörda.Denna modell föreslår, att alla som skulle bli berörda vid förändring, engagerar sig för att identifiera risker med assistering utav strategisk vägledning hos den lämpliga förvaltningen - Kommunal- og regionaldepartementet samt med det närvarande organisationspraxisesn av indentifiering av de objektiva miljöriskerna med råd ifrån ISO140001. Omfattningarna av byggplats-beroende och icke byggplatsberoende riskkategorier fokuseras på layouten av byggplats och byggmaterial, enligt företagetsåsikt vilken av dessa två riskgrupper som är viktigast. Riskshantering föreslås med fel träanlys (FTA) metoden till byggplats beroende risker och European Union System for the Evaluation of Substances (EUSES) till icke byggplats beroende risker.Helkostnadsbokföring (TCA) för projektets olika alternativ rekommenderas som åtgärd för att inkludera de vanliga ytterliggande kostnaderna. En två spårig integration av risksbeskedet föreslås – katagoriserad riskminskning vid projektsnivå och vanliga goda affärsprincipier tillsammans med riskmedvetenhet på policy nivå.På grund av att modellen är en ram för riskhantering, som skilljer sig ifrån en metod fören särskild risk, granskas priciperna så som föreslaget med fallstudier för identifieringoch analys av risker.Genom att engagera aktieägare och andra intressenter men även natuvetenskaplig riskbedömning, ska denna modell hjälpa företaget till att möjligöra en säker bedrivningutav företagspraxisen i kombination med ett stärkt intresse utav miljöaspekter. I framtiden ska detta i sin tur ge företaget större kompetens när det gäller att planera och skapa en hållbar affärsplanering. / www.ima.kth.se

For railways, risk analysis is carried out to identify hazardous situations and their consequences. Until recently, classical methods such as Fault Tree Analysis (FTA) and Event Tree Analysis (ETA) were applied in modelling the linear and logically deterministic aspects of railway risks, safety and reliability. However, it has been proven that modern railway systems are rather complex, involving multi-dependencies between system variables and uncertainties about these dependencies. For train derailment accidents, for instance, high train speed is a common cause of failure; slip and failure of brake applications are disjoint events; failure dependency exists between the train protection and warning system and driver errors; driver errors are time dependent and there is functional uncertainty in derailment conditions. Failing to incorporate these aspects of a complex system leads to wrong estimations of the risks and safety, and, consequently, to wrong management decisions. Furthermore, a complex railway system integrates various technologies and is operated in an environment where the behaviour and failure modes of the system are difficult to model using probabilistic techniques. Modelling and quantification of the railway risk and safety problems that involve dependencies and uncertainties such as mentioned above are complex tasks. Importance measures are useful in the ranking of components, which are significant with respect to the risk, safety and reliability of a railway system. The computation of importance measures using FTA has limitation for complex railways. ALARP (As Low as Reasonably Possible) risk acceptance criteria are widely accepted as ’\'best practice’’ in the railways. According to the ALARP approach, a tolerable region exists between the regions of intolerable and negligible risks. In the tolerable region, risk is undertaken only if a benefit is desired. In this case, one needs to have additional criteria to identify the socio-economic benefits of adopting a safety measure for railway facilities. The Life Quality Index (LQI) is a rational way of establishing a relation between the financial resources utilized to improve the safety of an engineering system and the potential fatalities that can be avoided by safety improvement. This thesis shows the application of the LQI approach to quantifying the social benefits of a number of safety management plans for a railway facility. We apply Bayesian Networks and influence diagrams, which are extensions of Bayesian Networks, to model and assess the life safety risks associated with railways. Bayesian Networks are directed acyclic probabilistic graphical models that handle the joint distribution of random variables in a compact and flexible way. In influence diagrams, problems of probabilistic inference and decision making – based on utility functions – can be combined and optimized, especially, for systems with many dependencies and uncertainties. The optimal decision, which maximizes the total benefits to society, is obtained. In this thesis, the application of Bayesian Networks to the railway industry is investigated for the purpose of improving modelling and the analysis of risk, safety and reliability in railways. One example application and two real world applications are presented to show the usefulness and suitability of the Bayesian Networks for the quantitative risk assessment and risk-based decision support in reference to railways.

For railways, risk analysis is carried out to identify hazardous situations and their consequences. Until recently, classical methods such as Fault Tree Analysis (FTA) and Event Tree Analysis (ETA) were applied in modelling the linear and logically deterministic aspects of railway risks, safety and reliability. However, it has been proven that modern railway systems are rather complex, involving multi-dependencies between system variables and uncertainties about these dependencies. For train derailment accidents, for instance, high train speed is a common cause of failure; slip and failure of brake applications are disjoint events; failure dependency exists between the train protection and warning system and driver errors; driver errors are time dependent and there is functional uncertainty in derailment conditions. Failing to incorporate these aspects of a complex system leads to wrong estimations of the risks and safety, and, consequently, to wrong management decisions. Furthermore, a complex railway system integrates various technologies and is operated in an environment where the behaviour and failure modes of the system are difficult to model using probabilistic techniques. Modelling and quantification of the railway risk and safety problems that involve dependencies and uncertainties such as mentioned above are complex tasks. Importance measures are useful in the ranking of components, which are significant with respect to the risk, safety and reliability of a railway system. The computation of importance measures using FTA has limitation for complex railways. ALARP (As Low as Reasonably Possible) risk acceptance criteria are widely accepted as ’\'best practice’’ in the railways. According to the ALARP approach, a tolerable region exists between the regions of intolerable and negligible risks. In the tolerable region, risk is undertaken only if a benefit is desired. In this case, one needs to have additional criteria to identify the socio-economic benefits of adopting a safety measure for railway facilities. The Life Quality Index (LQI) is a rational way of establishing a relation between the financial resources utilized to improve the safety of an engineering system and the potential fatalities that can be avoided by safety improvement. This thesis shows the application of the LQI approach to quantifying the social benefits of a number of safety management plans for a railway facility. We apply Bayesian Networks and influence diagrams, which are extensions of Bayesian Networks, to model and assess the life safety risks associated with railways. Bayesian Networks are directed acyclic probabilistic graphical models that handle the joint distribution of random variables in a compact and flexible way. In influence diagrams, problems of probabilistic inference and decision making – based on utility functions – can be combined and optimized, especially, for systems with many dependencies and uncertainties. The optimal decision, which maximizes the total benefits to society, is obtained. In this thesis, the application of Bayesian Networks to the railway industry is investigated for the purpose of improving modelling and the analysis of risk, safety and reliability in railways. One example application and two real world applications are presented to show the usefulness and suitability of the Bayesian Networks for the quantitative risk assessment and risk-based decision support in reference to railways.:ACKNOWLEDGEMENTS IV ABSTRACT VI ZUSAMMENFASSUNG VIII LIST OF FIGURES XIV LIST OF TABLES XVI CHAPTER 1: Introduction 1 1.1 Need to model and quantify the causes and consequences of hazards on railways 1 1.2 State-of-the art techniques in the railway 2 1.3 Goals and scope of work 4 1.4 Existing work 6 1.5 Outline of the thesis 7 CHAPTER 2: Methods for safety and risk analysis 10 2.1 Introduction 10 2.1.1 Simplified risk analysis 12 2.1.2 Standard risk analysis 12 2.1.3 Model-based risk analysis 12 2.2 Risk Matrix 14 2.2.1 Determine the possible consequences 14 2.2.2 Likelihood of occurrence 15 2.2.3 Risk scoring matrix 15 2.3 Failure Modes & Effect Analysis – FMEA 16 2.3.1 Example application of FMEA 17 2.4 Fault Tree Analysis – FTA 19 2.5 Reliability Block Diagram – RBD 22 2.6 Event Tree Analysis – ETA 24 2.7 Safety Risk Model – SRM 25 2.8 Markov Model – MM 27 2.9 Quantification of expected values 31 2.9.1 Bayesian Analysis – BA 35 2.9.2 Hazard Function – HF 39 2.9.3 Monte Carlo (MC) Simulation 42 2.10 Summary 46 CHAPTER 3: Introduction to Bayesian Networks 48 3.1 Terminology in Bayesian Networks 48 3.2 Construction of Bayesian Networks 49 3.3 Conditional independence in Bayesian Networks 51 3.4 Joint probability distribution in Bayesian Networks 52 3.5 Probabilistic Inference in Bayesian Networks 53 3.6 Probabilistic inference by enumeration 54 3.7 Probabilistic inference by variable elimination 55 3.8 Approximate inference for Bayesian Networks 57 3.9 Dynamic Bayesian Networks 58 3.10 Influence diagrams (IDs) 60 CHAPTER 4: Risk acceptance criteria and safety targets 62 4.1 Introduction 62 4.2 ALARP (As Low As Reasonably Possible) criteria 62 4.3 MEM (Minimum Endogenous Mortality) criterion 63 4.4 MGS (Mindestens Gleiche Sicherheit) criteria 64 4.5 Safety Integrity Levels (SILs) 65 4.6 Importance Measures (IMs) 66 4.7 Life Quality Index (LQI) 68 4.8 Summary 72 CHAPTER 5: Application of Bayesian Networks to complex railways: A study on derailment accidents 73 5.1 Introduction 73 5.2 Fault Tree Analysis for train derailment due to SPAD 74 5.2.1 Computation of importance measures using FTA 75 5.3 Event Tree Analysis (ETA) 78 5.4 Mapping Fault Tree and Event Tree based risk model to Bayesian Networks 79 5.4.1 Computation of importance measures using Bayesian Networks 81 5.5 Risk quantification 82 5.6 Advanced aspects of example application 83 5.6.1 Advanced aspect 1: Common cause failures 83 5.6.2 Advanced aspect 2: Disjoint events 84 5.6.3 Advanced aspect 3: Multistate system and components 84 5.6.4 Advanced aspect 4: Failure dependency 85 5.6.5 Advanced aspect 5: Time dependencies 85 5.6.6 Advanced aspect 6: Functional uncertainty and factual knowledge 85 5.6.7 Advanced aspect 7: Uncertainty in expert knowledge 86 5.6.8 Advanced aspect 8: Simplifications and dependencies in Event Tree Analysis 86 5.7 Implementation of the advanced aspects of the train derailment model using Bayesian Networks. 88 5.8 Results and discussions 92 5.9 Summary 93 CHAPTER 6: Bayesian Networks for risk-informed safety requirements for platform screen doors in railways 94 6.1 Introduction 94 6.2 Components of the risk-informed safety requirement process for Platform Screen Door system in a mega city 97 6.2.1 Define objective and methodology 97 6.2.2 Familiarization of system and information gathering 97 6.2.3 Hazard identification and hazard classification 97 6.2.4 Hazard scenario analysis 98 6.2.5 Probability of occurrence and failure data 99 6.2.6 Quantification of the risks 105 6.2.6.1. Tolerable risks 105 6.2.6.2. Risk exposure 105 6.2.6.3. Risk assessment 106 6.3 Summary 107 CHAPTER 7: Influence diagrams based decision support for railway level crossings 108 7.1 Introduction 108 7.2 Level crossing accidents in railways 109 7.3 A case study of railway level crossing 110 7.4 Characteristics of the railway level crossing under investigation 111 7.5 Life quality index applied to railway level crossing risk problem 115 7.6 Summary 119 CHAPTER 8: Conclusions and outlook 120 8.1 Summary and important contributions 120 8.2 Originality of the work 122 8.3 Outlook 122 BIBLIOGRAPHY 124 APPENDIX 1 131