Analysis and Evaluation of TIH Material Transportation by Railroad

The safety of hazardous material (hazmat) transportation is an important national issue. Although rail transportation plays a major role in hazmat movement, there is still not so much concern as that for highway. However, for the safety of life and property, more work in this filed is needed. This paper develops a risk evaluation methodology for rail Toxic Inhalation Hazard (TIH) material transportation. Here, the risk metric is defined as the product of incident probability and its consequence. First, we discuss the probability calculation of a specific incident case, i.e. there are a specific number of derailed TIH cars releasing, given a train crash. Second, we employ the rearranged Gaussian Plume Model to get the hazardous gas concentration isopleth and the impact zone. From this, the consequence defined as population exposure is calculated by multiplying impact zone area and relevant population density. Finally, with the evaluation methodology proposed in the paper, we calculated and compared risk between two rail routes in the state of Tennessee.