Findings of TSB investigation (R16T0111)

Uncontrolled movement of rolling stock at MacMillan Yard near Toronto, Ontario, June 2016

Investigations conducted by the Transportation Safety Board of Canada (TSB) are complex – an accident is never caused by a single factor. The June 2016 uncontrolled movement of railway cars at MacMillan Yard in Vaughan, Ontario, was no exception. Many factors contributed to the accident, the details of which are contained in the 11 findings as to causes and contributing factors. The investigation established 6 additional findings, including 3 findings as to risk.

Findings as to causes and contributing factors

  1. The crew had not supplied air to the head-end cars, leaving only the locomotive independent brakes to control the 9116-ton, 4537-foot-long assignment as it accessed the main track.
  2. To prepare to stop the assignment at the request of the foreman, the assignment helper applied the locomotive independent brakes, but the assignment continued to accelerate.
  3. With about 64% of the assignment length (about 2900 feet of a total of 4537 feet) and weight (about 5830 tons of a total of 9116 tons) occupying the 0.70% eastward descending grade, the locomotive independent brakes alone were unable to control the assignment.
  4. The helper placed the assignment into emergency, but, with no supply of air in the train air brake line, emergency brakes were not available on any of the freight cars. Emergency application of the locomotive independent brakes was insufficient to stop the assignment.
  5. The assignment continued to accelerate and roll uncontrolled, reaching a speed of almost 30 mph before stopping on an ascending grade at Mile 21.1 of the York Subdivision, just before it would have accessed the Bala Subdivision.
  6. The west industrial job aid was unclear as to when air should be applied to some or all of the cars and did not identify all the hazards associated with taking head room on the York Subdivision when moving cars to the west industrial yard.
  7. The trainmaster understood the job aid guidance to mean that all equipment being moved should have operative air brakes, whereas the crew understood the guidance to mean that air must be applied to the cars before they were left at some customer facilities. This misunderstanding was neither identified nor resolved during the job briefings.
  8. The procedures available to the assignment crew did not provide sufficient guidance to decide when a yard movement was too long and too heavy to rely solely on the locomotive independent air brakes to control the movement.
  9. The assignment crew did not have sufficient operational experience to safely perform the tasks of the west industrial yard assignment at MacMillan Yard.
  10. Conductors receive little training in locomotive operation and train handling, and the current Railway Employee Qualification Standards Regulations do not require such training.
  11. While the assignment crew members were aware of the assignment's length and weight, they lacked the knowledge to fully understand the effect of these factors on train handling while descending a 0.70% grade with only locomotive independent brakes available to control the assignment.

Findings as to risk

  1. If yard assignment job aids do not identify all hazards that switching assignments may encounter while working, there is an increased risk that assignment crews may encounter a situation or topography that could result in an uncontrolled movement.
  2. If safeguards are not in place to ensure that crews possess sufficient operational experience to work a given assignment, there is an increased risk of operational errors and accidents.
  3. If the current Railway Employee Qualification Standards Regulations are not updated, gaps will remain, and Transport Canada will not be able to conduct effective regulatory oversight and enforcement of training programs for safety-critical positions such as management and unionized operating crews, remote control locomotive system operators, rail traffic controllers, and contract trainers, increasing the risk of unsafe train operations.

Other findings

  1. The quick reaction by the foreman and the rail traffic controller to protect the uncontrolled assignment minimized the risk of collision and of a more serious outcome.
  2. Since yard positions are typically assigned to operating employees with the least seniority, it is not uncommon for a yard crew to consist of 2 conductors with limited operational and remote control locomotive system experience.
  3. The number of occurrences involving uncontrolled movements (i.e., runaway rolling stock) increased by about 10% in the past 5 years, as compared to the 10-year average.
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