A systematic review of MBSE-based safety analysis techniques in railway systems

With the development of railway systems towards intelligence, informatization and networking, their architecture design becomes increasingly complex. Traditional safety analysis methods (such as failure mode and effects analysis (FMEA), fault tree analysis (FTA) and event tree analysis) can no longer realise integrated safety analysis across disciplines, domains and life cycles amid requirement drift, architecture iteration and operational scenario evolution. This paper aims to introduce a systematic, integrated, model-driven safety analysis framework for the entire life cycle of railway systems to address these complex safety challenges and improve the overall safety level of railway systems.

First, the paper conducts a literature review of traditional railway safety analysis techniques and their applications, and analyzes the technical framework, core elements (modelling languages, methods, and tools), and advantages of Model-Based Systems Engineering (MBSE). Then, it studies the integration of MBSE and system safety analysis, focusing on typical international research cases (e.g., the Methodology for the Description and Safety Analysis of Interoperable Systems (MeDISIS), the European Train Control System (ETCS) safety verification project SafeSysE, and the Reference Architecture for Model-Based System and Software Engineering in the Railway Domain (RAMSAS), etc.) and domestic research progress, and summarizes the core idea of integrating MBSE with safety analysis in the design process. Finally, it explores the key technologies of MBSE-based railway system safety analysis, including automatic mapping of architecture models to Fault Tree Analysis (FTA), dynamic linkage between behaviour models and Failure Mode and Effects Analysis (FMEA), multi-model collaboration and dynamic update, as well as technologies in three aspects: safety requirement analysis driven by railway operational tasks, integrated safety-function design analysis, and simulation-based safety verification via train-fleet operation modelling. The development and validation platform Platform for Integrated Systems and Mechatronic Engineering (PRISME) and tools such as the Dependability Engineering and Innovation System (DEIS), Behavior-Driven Development (BDD) frameworks, and International Business Machines (IBM) engineering suites were also utilized to support this research.

The MBSE-based railway system safety analysis technique embeds safety activities into the forward-engineering workflow of MBSE-driven development, enabling concurrent safety and functional design. It solves the problems of model heterogeneity, data silos and process discontinuities in traditional safety analysis and realises end-to-end traceability and consistency from system requirements to safety analysis results. This technique not only provides a rigorous foundation for standardised, efficient and accurate safety assessment of railway systems but also offers technical support for early identification of potential safety issues, reduction of late-stage design changes and continuous optimisation of system safety performance.

The innovation of this paper mainly includes three aspects:(1) It breaks the limitations of traditional document-driven safety analysis methods, constructs an MBSE-based integrated safety analysis framework covering the entire life cycle of railway systems and turns safety work from an ad-hoc add-on into a systematic, goal-oriented activity. (2) It proposes key integration technologies such as automatic mapping of SysML-based architecture models to FTA, dynamic linkage between behaviour models (state machine diagram/activity diagram) and FMEA and multi-model (FTA/FMEA/hazard and operability analysis) collaborative dynamic update, which guarantee the consistency and traceability of safety analysis data and improve the efficiency of safety analysis iteration. (3) It develops a set of MBSE-based railway safety analysis implementation paths, including task-driven safety requirement decomposition, integrated safety function failure propagation modelling and train-fleet operation simulation-based verification, providing a practical technical solution for the safety design and analysis of complex railway systems.