Practical UML subset for railway engineers to support formal modeling

    Trans Motauto World, Vol. 7 (2022), Issue 2, pg(s) 56-59

    The acceptance and popularity of formal modeling is increasing in the development of safety-critical railway interlocking systems, because it allows the specification of the system’s functionality using mathematically rigorous rules. The goal of the research described here is to introduce a simple, easy-to-learn, and useful UML (Unified Modeling Language) subset that supports railway engineers in developing the functionality of system elements at the system planning level. The selection of this UML subset is based on our practical experience. We examine the properties and limitations of this subset through a case study using the Yakindu Statechart Tools. The components specified with the proposed UML subset can be easily transformed into timed automata that we studied using the UPPAAL framework. In the paper, we also present the UPPAAL model for the case study. We are currently working on the implementation of a transformation using the UML subset presented in this paper, which makes it possible to generate formal models from Yakindu to UPPAAL in an automated way.


    Issues regarding the rolling highways

    Trans Motauto World, Vol. 6 (2021), Issue 3, pg(s) 96-103

    Very popular among the environment activists and public authorities, the rolling highways prove to have a poor commercial viability. Therefore, the paper tries to find the reasons for this fact. The analysis starts with the descriptions of the technical solutions, then the traffic volumes recorded on different transport relations / countries are presented, together with the main findings from the European experience. The trends are explained considering the operational issues, the transport costs, the factors influencing the demand, the state support and the railway regulations, as well as the requirements of the customers. Special comments are focused on the Romanian experience, indicating the operational issues specific to Romania, the necessity for state aids with intensities of 45 – 60% from the costs, as well as the savings in external costs. The main conclusions are that the rolling highways are environmentally friendly, but costly and that they could develop only if the public authorities implement appropriate support measures and aids.