Technical Reports

Risk Evaluation Framework and Selected Metrics for Tank Cars Carrying Hazardous Materials

  • 07
  • May
  • 2015
AUTHOR: Federal Railroad Administration
SUBJECT: Hazardous Materials
KEYWORDS: Risk Evaluation Framework and Selected Metrics for Tank Cars Carrying Hazardous Materials; Risk evaluation; tank car; toxic by inhalation; poisonous by inhalation; hazardous materials
ABSTRACT: This report presents an analysis of train accident and hazmat release data to quantify the likelihood of a hazmat release. The harm caused by a hazmat release is characterized as the end result of a chain of events, with each link in the chain being characterized by risk metrics that determine likelihood of occurrence. The chain of events is typically comprised of the following: 1) Freight train accident (due to an infrastructure or equipment defect) failure of signal or communications equipment, human error, or miscellaneous cause; 2) One or more freight cars derailed in accident, as a function of accident type, train speed, etc.; 3) Hazmat tank cars among derailed cars, depending on hazmat car routing practice; 4) Derailed hazmat tank car releases following a train accident; and 5) Harm to people, property, and/or the environment from exposure to released hazmat. Analysis and findings in this report will provide regulatory, industry, and general public stakeholders a better understanding of the “chain of events” leading to a hazmat release from a tank car, the impact of risk reduction measures that can be applied at different links along the chain of events, and a quantifiable risk model representing the chain of events leading to a hazmat release.