Study On Operational Safety And Reliability Of Urban Mass Transit System

Today, a lot of medium-sized and large cities in China are accelerating the construction of urban mass transit (UMT). The UMT is playing an increasingly important role in urban development and the urban residents' daily work and life; therefore, to strengthen and promote its operational safety and reliability has become a subject of great concern.Based on the safety science theory and reliability engineering theory, the frameworks of operational safety and operational reliability are proposed. The safety framework includes safety technology system, safety management system, emergency disposal system and safety study system. The reliability framework includes reliable technology system, reliability maintainability system, maintenance technology system and reliability study system.Attempts have been made in this paper to find ways of constructing safety analysis model for UMT operational safety on the basis of Preliminary Hazard Analysis (PHA) and Petri net theory. A dynamic safety analysis model for the platform screen doors was established. Based on the Reliability Theory, an index system of UMT operational safety was constructed. A preliminary hazard analysis was made on the UMT operational safety including System Hazard Analysis (SHA), Sub-System Hazard Analysis (SSHA), Interface Hazard Analysis (IHA), Operating and Support Hazard Analysis, (O&SHA), and Safety Critical Item List (SCIL). Based on the preliminary hazards analysis that covers the whole UMT, some potential dangerous situations and trigger events have been exposed and the causes and possible consequences as well as the occurrence frequency and gravity of the consequences have been analyzed and evaluated.Efforts have been made in this paper to establish a preliminary framework of UMT reliability function and a fault tree model based on a hypothesis that a subway often breaks down. Based on the operational characters of UMT and the principles of Hierarchical Petri net and Object-oriented Petri net, a Hierarchical Object-oriented Colored stochastic Petri Net (HOPN) is proposed and used to establish a dynamic analysis model for UMT operational reliability. An index system of UMT operational reliability and a sampled way of appraising the operational reliability of the existing transit are proposed. failure mode effect and criticality analysis (FMECA) is made on...