Following several recent serious rail accidents in North America, changes in regulation and increased public awareness is driving the need to address gaps in rail safety. The industry and regulators have numerous safety initiatives; however prescriptive standards in combination with a performance based approach could be a powerful tool for understanding and mitigating risk in a cost effective way.
This paper reviews the principles of safety risk management that can be applied to safe transportation of flammable hydrocarbons by Rail. FRA’s proposed rulemaking on Risk reduction program and its potential impact on the industry are also addressed.
The approach proposed in this paper focuses on existing and new proposed safeguards/barriers and how they could be monitored and managed. The paper aims to set the path forward for structured risk based thinking in managing rail safety. The first part of the paper explains the barrier based risk assessment approach using the Lac Megantic accident as an example. A bow-tie is developed to deconstruct the incident timeline and to capture the safeguards that existed at that time and their working status. This diagram cross references Transport Canada’s Investigation findings.
The second part of the paper evaluates the new mitigation measures proposed by FRA HM 251 rulemaking (“Enhanced Tank Car Standards and Operational Controls for High-Hazard Flammable Trains” Final Rulemaking”) as potential safeguards and their impact on the overall risk of transportation. A baseline risk is first established for transporting crude by rail assuming some common safeguards in place. A simple Quantitative Risk Assessment methodology including likelihood and consequence was then used to estimate the base case risk. Risk mitigation and effect of any additional new measures like Changes in Rail Tank Car design, Oil Conditioning, Enhanced Braking to Mitigate Damage in Derailments, Speed Limit changes, Positive train control, Train manning when loading are assessed.