Conditional value-at-risk (CVaR) methodology to optimal train configuration and routing of rail hazmat shipments

Hazardous materials (hazmat) incidents are rare though the consequences could be catastrophic. The low probability–high consequence nature of such events mandate that a risk-averse plan be implemented for routing hazmat shipments. We propose a conditional value-at-risk (CVaR) methodology for routing rail hazmat shipments, using the best train configuration, over a given railroad network using the pre-defined train services such that the transport risk as measured by CVaR is minimized. Freight train derailment records were analyzed to model the behavior of railroad accidents, and to estimate conditional probabilities. The proposed methodology was used to study several problem instances generated using the realistic network of a railroad operator, and to demonstrate that the proposed methodology is superior to other measures for risk-averse routing of hazmat shipments and versatile enough to yield routes based on risk preferences of the decision makers.