Comparing Unit Trains versus Manifest Trains for the Risk of Rail Transport of Hazardous Materials -- Part II: Application and Case Study

Built upon the risk analysis methodology (presented in the part I paper), this part II paper focuses on applying this methodology. Five illustrative scenarios were used to analyze the best or worst cases and compare the transportation risk differences between service options using unit trains and manifest trains. The comparison results indicate that if all tank cars are placed at the positions with the lowest probability of derailing and if switching tank cars alone in classification yards, it could provide the lowest risk estimate given the same transportation demand (i.e., number of tank cars to transport). This paper also shows that based on the data and parameters in the case study, risks during arrival/departure events and yard switching events could be as significant as risks that on mainlines. This paper provides a way to use the risk analysis methodology for rail safety decisions. The methodology and its application can be tailored to specific infrastructure and rolling stock characteristics.