Analysis of rail accident by combining of FTA and Tripod-Beta techniques in Tehran Subway

Due to that there is high sensitivity to safety in the rail industry,and considering the wide range of adverseconsequences,the people involved in the incident,requires continuous monitoring operation,strengthenthe identification,assessment,reduction,if possible elimination of hazards In this context felt. In thispaper,a comprehensive approach to identify hazard,assess the critical paths,analysis of the barriersof the rail system that by combining two methods of Fault tree analysis,Tripod-beta techniques the causeof incident have been detected effectively,deeper in the organizational layers. By combining these twomethods improved the root causes analysis of the incident,the reasons for the failure barriers deeply andeffectively. In this paper,considered “accident of two urban train as top event in the fault tree,defined in thatthree factors “inability of the command center,the inability of ATP,the inability of signal lights” to preventthe accident of two trains as the main barriers (That were failure led to accident. Then,the basic events wereused as Tripod-beta technique inputs to investigate the chain causes of the accident (the immediate cause,theprecondition,underline cause) at the completion of the fault tree. So,according to the opinions of expertsin the field,using fuzzy logic the probability of the top event is calculated with 0.006 weight,havebeen detected the critical paths. The main objectives of this paper are to investigate the possibility of combiningtwo methods of fault tree analysis,Tripod-beta,fix flaws of the composition,analysis of factors in thecollision of two subway trains in Tehran.