Quantitative risk assessment method for the on-board ATP of high-speed railway

With the great improvement of operational speed of trains, the on-board ATP of the high-speed railway plays an essential role in train's safe operation as a major component of the signal system. Therefore, it is necessary and important to identify and assess risks in the on-board ATP. In this paper, a quantitative risk assessment method is proposed based on the Bow-tie model. Event trees are exploited for the graphical presentations of accident evolution path from risks. Moreover, it can quantitatively evaluate the accident probabilities and frequencies. The potential risks of system have been identified as well as system's weak link by fault tree analysis, which are the initial events of event tree. Combined with the ALARP principle with F-N curve, the risk acceptable level may be determined. In addition, the safety integrity level of system can be revaluated correctly. Finally, in the case study, the method is applied to analyze the on-board ATP.