On the industrial uptake of formal methods in the railway domain: A survey with stakeholders

The railway sector has seen a large number of successful applications of formal methods and tools. However, up-to-date, structured information about the industrial usage and needs related to formal tools in railways is limited. As a first step to address this, we present the results of a questionnaire submitted to 44 stakeholders with experience in the application of formal tools in railways. The questionnaire was oriented to gather information about industrial projects, and about the functional and quality features that a formal tool should have to be successfully applied in railways. The results show that the most used tools are, as expected, those of the B family, followed by an extensive list of about 40 tools, each one used by few respondents only, indicating a rich, yet scattered, landscape. The most desired features concern formal verification, maturity, learnability, quality of documentation, and ease of integration in a CENELEC process. This paper extends the body of knowledge on formal methods applications in the railway industry, and contributes with a ranked list of tool features considered relevant by railway stakeholders.