Why Engineering Disasters Happen — The Lac-Mégantic Disaster (2013)

June 5, 2024 — 10:30–11:45 a.m.

In the early hours of July 6, 2013, a runaway unit train carrying petroleum crude oil operated by Montreal, Maine & Atlantic Railway (MMA) derailed in the core of Lac-Mégantic, Quebec, with ensuing fire and explosions. The train travelled approximately 7.2 miles, reaching a top speed of over 100 km/hr. When the train approached the centre of the town, 63 tank cars carrying petroleum crude oil (UN 1267) and two box cars derailed, spilling about six million litres of petroleum crude oil. This incident was one of the deadliest rail accidents in Canadian history. This case study explores the sequence of events and engineering causes of an entirely preventable incident that led to 47 lives lost, infrastructure loss in the centre of town, and significant impacts to the environment.

Several engineering failures contributed to the disaster, not limited to the following:

  1. Train securement: The train was not properly secured, with the locomotive not running and insufficient handbrakes applied.
  2. Train operation: The train was parked on a descending grade outside Lac-Mégantic for a crew change. The locomotive, which was supposed to provide air brake pressure to keep the train stationary, was shut down, and the handbrakes were not applied properly. As a result, the train started rolling downhill towards the town.
  3. Engine maintenance: Eight months prior to the incident, the lead locomotive was sent for repairs due to an engine failure. The OEM (original equipment manufacturer) would recommend using a new part, however the MMA locomotive engine was not repaired per manufacturer’s specifications, nor specifications approved by a professional engineer.
  4. Tank car design: The tank cars used were older DOT-111 models, known for their vulnerability to puncture and rupture during accidents.
  5. Route selection: The decision to route trains carrying hazardous materials through populated areas without adequate safeguards and emergency response plans contributed to the severity of the incident.

The conference session examines the critical weaknesses and failures in various risk management system elements that ultimately caused the incident, as well as the lessons learned for leadership in engineering safety and risk management in any organization. The Lac-Mégantic disaster underscores the importance of proactive risk management, robust engineering practices, and regulatory oversight in preventing catastrophic incidents involving hazardous materials transportation.

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