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.

This paper focuses on studying the reliability allocation for the railway system, aiming to improve the overall reliability of the railway system and ensure safety operation.

In view of the complex structure of the railway system, involving many subsystems, this paper analyzes the close dynamic coupling effect between railway subsystems. Based on this, taking the railway system failure as the top event, a fault tree is constructed in this paper. Then, a reliability allocation method based on the fault tree is employed to allocate the reliability index. Finally, a numerical experiment is implemented to show the performance of the reliability allocation method.

The results showed that each subsystem needs to improve its reliability to meet the specified railway system reliability requirements, and the traction power supply system is the most important subsystem, which is the most efficient in improving the reliability of the railway system.

For the first time, starting from a holistic perspective of the system, reliability allocation is carried out based on the importance of each railway subsystem.

Safety management is a key point and poses a challenge in joint testing. To detect and address potential accidents' hidden dangers early, this paper conducts research on the safety control technology for high-speed railway joint tests by incorporating the concept of hazardous events.

Aiming at ensuring the safety of high-speed railway combined inspections and trials, this paper starts from the dual prevention mechanism. It introduces the concept of threatening events, defines them and analyzes the differences between threatening events and railway accidents. The paper also proposes a cause model for threatening events in high-speed railway combined inspections and trials, based on three types of hazard sources. Furthermore, it conducts research on the control strategies for these threatening events.

The research on safety control technology for high-speed railway combined operation and testing, based on the analysis of threatened events, offers a new perspective for safety management in these operations. It also provides theoretical and practical support for the transition from passive prevention to active risk pre-control, which holds significant theoretical and practical value.

The innovation mainly includes the following three aspects: (1) Building on the traditional dual prevention mechanism, which includes risk hierarchical management and control as well as hidden danger investigation and management, a triple prevention mechanism is proposed. This new mechanism adds the management of threatening events as the third line of defense. The aim is to more comprehensively identify and address potential security risks, thereby enhancing the efficiency and effectiveness of security management. (2) In this paper, the definition of a railway threatening event is clarified, and the causative model of a high-speed railway threatening event based on three kinds of danger sources is proposed. (3) This paper puts forward the control strategy of the high-speed railway combined operation and trial, which includes five key links: identification, reporting, analysis, rectification and feedback, which provides a new perspective for the safety management of the high-speed railway combined operation and trial and has important theoretical and application value.