This book constitutes the proceedings of the 5th International Conference on Reliability, Safety, and Security of Railway Systems. Modelling, Analysis, Verification, and Certification, RSSRail 2023, held in Berlin, Germany, during October 10–12, 2023. The 13 full papers presented in this book together with 3 keynotes were carefully reviewed and selected from 25 submissions. The papers are divided into the following topical sections: modeling for security; tooled approaches and dependability of highly automated transport systems; formal methods for safety assessment; and formal model and visual tooling.