ABSTRACT
Megacities across the world will continue to grow during the 21st century. Urban Rail Transit Systems (URTS) in such cities are subject to different hazards, which can lead to life safety risks. It motivates transport researchers to prepare for the growing risks, which megacities pose to its URTS. For instance, the higher the number of users of a URTS, the greater the life safety risks will be, provided that an accident occurs due to any reason. Platform Screen Doors (PSD) are increasingly utilised to minimise the life safety risks at the interfaces of over occupied trains and platforms in megacities. The planners and engineers try to identify the safety requirements a PSD system has to fulfil under specific operational, environmental and socio-economic conditions. In the railway industry, these safety requirements are considered with Safety Integrity Levels (SIL). The SIL requirements must be agreed by all stakeholders. This study proposes a generic framework to assess the life safety risks in URTS and how it can be applied to determine the SIL requirements for a safety technology. A case study is presented on the PSD system, which aims to minimise the life safety risks in URTS. A number of hazardous situations are identified. A preliminary cause and consequence analysis is carried out to scrutinise the most important hazardous situations leading to the life safety risks. Quantitative risk analysis of the most important hazardous situations is performed for specific operational conditions. The risks are then compared against “best practice” risk acceptance criteria and the SIL requirements are determined for the PSD system. The proposed framework can be useful for engineering systems where risk-informed safety requirements and associated SIL levels need to be determined.
