Using Safety Requirement Patterns to Elicit Requirements for Railway Interlocking Systems

Safety requirements are of great importance in Railway Interlocking Systems. However it is still very difficult to obtain all of the safety requirements in practice. In this paper, we propose an approach to capture safety requirements based on safety requirements patterns. From a variety of sources, such as interlocking tables and existing safety relevant functional requirements of railway interlocking system, we classify them and extract some safety requirement patterns in formal descripitions. Finally, a process to elicit safety requirements based on these patterns are given. We applied our approach to the interlocking system at Mohe station in China.