Evaluating Railroad Track Upgrades to Reduce Transportation Risk

Transportation Research Record: Journal of the Transportation Research Board, No. 2261, Transportation Research Board of the National Academies, Washington, D.C., 2011, pp. 178–185. DOI: 10.3141/2261-21 structure and operational conditions. Track-related and equipmentrelated accident causes collectively result in the majority of train derailments in the United States. Understanding how they may be affected by approaches to derailment prevention is useful for developing and evaluating cost-effective strategies to reduce railroad transportation risk. Upgrading track quality is one possible derailment prevention strategy. FRA divides track quality into five principal classes commonly used by freight railroads in accordance with FRA track safety standards. Higher track classes have correspondingly higher maximum train speeds and more stringent track safety standards (1). Research has analyzed various safety and economic impacts of track class upgrade. Higher track classes are statistically correlated with lower derailment rates (2–4). Saat and Barkan developed an analytical model to compare the safety benefits of enhanced tank car safety design versus infrastructure improvement (5). Lai et al. developed an optimization framework to determine optimal track class assignment based on the minimization of track maintenance and transportation costs (6). Liu et al. presented a benefit–cost analysis framework to consider the trade-off between reduced accident rates and increased track maintenance costs in evaluating track class upgrade as a risk reduction strategy (7 ). Kawprasert proposed a biobjective model that simultaneously considers risk and investment costs in determining the best track infrastructure upgrade strategy (8). However, none of these investigations addressed how track class upgrade affects the risk pertaining to certain accident causes. Although upgrading track class is expected to prevent certain track-related derailments, it may also increase the risks from certain types of equipment failure that are more likely to occur at higher speeds. This study developed an accident cause–specific derailment risk model that simultaneously accounts for the interactions among different accident causes that may be differently affected by track class upgrade. The paper is structured as follows: a general framework for derailment risk analysis is introduced, followed by analyses and modeling of derailment rate, severity, and the corresponding risks. Finally, accident cause–specific derailment risk by FRA track class is estimated using derailment statistics from the FRA Accident/Incident Reporting System database and recent literature.