This book constitutes the refereed proceedings of the Third International Conference on Reliability, Safety, and Security of Railway Systems, RSSRail 2019, held in Lille, France in June 2019.

The 18 full papers presented in this book were carefully reviewed and selected from 38 submissions. They cover a range of topics including railways system and infrastructure advance modelling; scheduling and track planning; safety process and validation; modelling; formal verification; and security.