Train External Access Door model for digital twin simulator

This thesis presents the design and implementation of a simulation model of a Train External Access Door within a digital twin environment, developed in TrainLab . The work focuses on the AS300 project, aiming to reproduce the functional behavior of the external door system to support testing and validation activities in a safe and efficient virtual setting. A key motivation behind the study lies in the comparison between traditional text-based programming approaches and block-based modeling within the ControlBuild environment. In conventional workflows, door system functionalities are implemented with text-based languages, offering precision, scalability, and strong integration into industrial development pipelines. This approach supports robust debugging and comprehensive documentation, making it highly suitable for complex railway automation. In contrast, the thesis explores block-based modeling in ControlBuild, where logic is constructed through graphical connections. The project evaluates the trade-offs between the two methodologies. Advantages of block-based modeling include faster development cycles, visual clarity, and accessibility for engineers new to the system. Limitations include reduced adaptability and challenges in handling highly detailed logic. Conversely, text-based programming offers rigor, flexibility, and maintainability, but at the cost of greater complexity and longer development time. By analyzing these aspects, the thesis investigates whether block-based modeling can act as a viable complement or even a potential alternative to conventional approaches in train system design and digital twin simulation. The structure of the document reflects this dual technical and methodological objective. Chapter 2 introduces the railway context, with emphasis on safety, onboard systems, and the role of Alstom and TrainLab, alongside relevant regulatory standards. Chapter 3 presents the tools and technologies used, including ControlBuild, U-Test, and supporting software, as well as an overview of the AS300 train and its door systems. Chapter 4 describes the modeling activities, from requirement analysis to the implementation of logical blocks. Chapter 5 focuses on testing, illustrating the setup in TrainLab, test execution with U-Test, and the main results. Chapter 6 discusses the analysis of outcomes, identifying corrections and improvements. Chapter 7 concludes with an evaluation of the project’s contributions for the company and suggests directions for future work, such as test automation or extending the modeling approach to other train subsystems. Ultimately, the thesis demonstrates how digital twin-based simulations, developed with both block-based and text-based approaches, can enhance railway system validation by increasing reliability, reducing testing time, and minimizing operational risks. The study not only provides a functional model of the AS300 external access door but also contributes to a broader reflection on the role of modeling methodologies in the evolution of safety-critica