Semantic interpretation of a knowledge domain is usually required to provide and formalize its common vocabulary. This task is challenging in the context of Safety Critical Systems (SCSs) development, since it involves both safety and design teams. In the railway domain, there is a lack of a common vocabulary aiming to avoid ambiguities in the safety-related decisions to satisfy goals. To cope with the complexity of this task, the aim of this study is to propose a semantic interpretation of the safety rules development process from a goal-oriented perspective. The safety rules development process is performed according to the Organization-Based Access Control (Or-BAC) model, which is normally used for the information systems security. The proposed approach is based on a foundational ontology in order to interpret safety-related concepts in real-world semantics. It provides relations between safety-related concepts and Unified Foundational Ontology (UFO) concepts. Furthermore, the matching between safety rules, Or-BAC and Goal-Oriented Requirements Engineering (GORE) concepts is considered and formalized in a structured way. The proposed interpretation is evaluated and progressively justified regarding the railway domain knowledge and the current literature.