Study On Operation Safety Risk Modeling Of High-speed Railway Signaling System

Safety is the most vital topic of high-speed railway.Once an accident takes place during high-speed railway operation,it can directly lead to numerous injuries or even fatalities with huge economic losses.As the safety critical equipment of high speed railway system,the significance of signaling system is to ensure high-speed train safe and efficient running.With the introduction of a large number of new equipment and technologies,how to assure safety of the signaling system during operation has become an important challenge to be solved at the present stage.Safety risk assessment of China high speed railway operation is still in its early stage of development.The method of "more experience other than science" arisen from traditional railway industry is no longer applicable to the present high-speed railway industry.The current risk assessment methods used in domestic railway signaling system focus on controlling the risk of signaling equipment in the design process.Due to low-efficient usage of the equipment operation data on the side of operator,effective safety risk assessments cannot be reached,therefore,safety performance level of the signaling equipment cannot be acknowledged after its commissioning into operation,and consequently,equipment suppliers cannot be provided with more objective and reasonable safety targets,which leads to the deviation from the actual situation of operation safety,and suppliers cannot implement effective risk management during safety assurance.The paper,according to the current European railway safety assessment criteria,sets up a suitable assessment criterion for Chinese high-speed railway signaling system operation.Based on the system safety theories,using technologies of event tree analysis,fault tree analysis,Bayesian network and fuzzy modeling methods,this paper conducts a safety risk assessment modeling method for high-speed railway signaling system operation.The main research contents and results are as follows:Firstly,this paper summarizes the rationale between operation risk and signaling system operation risk combined with the actual situation of high-speed railway operation.Then this paper sets up the signaling system operation safety risk model based on fault tree analysis and event tree analysis,.Referring to the European common safety method the paper also sets up safety assessment criteria for the signaling system operators.Secondly,this paper studies the transformation rules of the operation safety risk model to the Bayesian network,and based on Bayesian network analysis model,the paper constructs the high-speed railway signaling system operation safety risk quantitative analysis model.Then the paper adopt the algorithm of expert evaluation and fuzzy theory for the root node prior probability determination.Finally,according to the actual operation requirements of one railway signal section and taking the change of point switch fault detection technology as an example,the paper studies the operational safety risk assessment of point switch monitoring system.The result proves that the method using event tree and fault tree,fuzzy theory and Bayesian network to set up the operational safety risk model is feasible.