Refining the Safety Design of Rail Tunnels in the EU Using Systems Thinking

Tunnels have developed from basic infrastructure into complex systems with many interconnected components. When designing a railway tunnel, other factors like human behavior and the technical systems of the trains add to this complexity. Traditional safety analysis methods often fall short in addressing this complexity, highlighting the need for a new approach to railway tunnel fire safety. This article sets out to investigate whether methods incorporating systems thinking into railway tunnel safety design could improve tunnel safety. A framework incorporating both STPA with more traditional engineering is used to analyze a prescriptive design as part of a case-study. Based on `common' fire scenarios for railway systems, results show that a prescriptive design provides inadequate control in protecting tunnel users from heat and smoke. The article reveals that while the current regulatory framework at the EU level aims to incorporate systems thinking into the design process, several critical gaps hinder its practical implementation. The integration of safety assessment methods based on systems-thinking, combined with traditional risk analysis methods, holds significant potential for improving railway tunnel safety design. By combining methods like STPA with tools such as CFD, designers can better analyze complex socio-technical interactions and provide robust, cost-effective safety solutions.

Keywords: Tunnel fire safety, Railway tunnel, Systems safety, STPA.