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Rail transportation safety investigation R18E0007

The TSB has completed this investigation. The report was published on 19 August 2020.

Table of contents

Uncontrolled movement of rolling stock

Canadian National Railway Company
Freight train L76951-10
Mile 0.5, Luscar Industrial Spur
Leyland, Alberta

View final report

The occurrence

On , at approximately 0228 Mountain Standard Time, Canadian National Railway Company freight train L76951-10, proceeding southward on the Luscar Industrial Spur from the Teck Resources Limited Cardinal River Operations coal loading facility near Cadomin, Alberta, experienced a loss of control while proceeding down the mountain grade to Leyland, Alberta. The train reached a maximum speed of 53 mph before it came to a stop at Mile 0.5. There were no injuries.

The uncontrolled movement of the train occurred when the available brake capacity was insufficient to control the train as it descended the steep mountain grade of the Luscar Industrial Spur. Inspection immediately after the train came to a stop revealed that the air brakes on 27 of the 58 loaded coal cars were not applied. While the train was at Luscar, the temperature dropped below a critical point, which adversely affected the function of the air brake control valves on the cars in this train. At the time of the occurrence, the ambient temperature was −24 °C.

Worn rubber seals from the bottom cover exhaust port of the DB-10 service portions of the air brake control valves experienced shrinkage in the extreme cold temperatures that resulted in auxiliary reservoir leakage and the unintended release of brakes on 27 freight cars following service air brake applications. Even though previous performance issues with the DB-10 service portion control valves had manifested themselves in cold weather and resulted in an Association of American Railroads (AAR) Circular in 2013, the failure mode that was previously identified was repeated in this occurrence. If performance issues involving rubber components in air brake control valves are not fully analyzed when they occur, degradation in the efficacy of the control valve, particularly during cold weather conditions, may not be identified and addressed in a timely manner, increasing the risk of a loss of control event.

Safety communication

Safety advisories


Rail Safety Advisory Letter 04/18: Potential brake valve failures on cars that have been in long term storage

Media materials

News releases


2018 uncontrolled movement of coal train in Luscar, Alberta highlights risks of operating trains on steep mountain grades during extreme cold temperatures
Read the news release

Deployment notice


TSB deploys a team of investigators following runaway train incident near Luscar, Alberta

The Transportation Safety Board is deploying a team of investigators following a runaway train incident near Luscar, Alberta. There was no derailment or dangerous goods released. The TSB will gather information and assess the occurrence.

Investigation information

Map showing the location of the occurrence


Photo of Don Crawford

Don Crawford has many years of national and international railway experience. In his early career, he was a locomotive engineer with Canadian National (CN) Railway on its British Columbia North Corridor and Vancouver based territories and with BC Rail on the former BC Rail property. In addition, Mr. Crawford has experience in training and supervisory roles and was a staff member at CN's Gimli, Manitoba training facility. Internationally, Mr. Crawford worked in Kosovo after the 1998/99 war as part of the United Nations Peace Keeping effort helping to restore rail service to the country. Most recently, Mr. Crawford worked in Saudi Arabia as a locomotive instructor.

Class of investigation

This is a class 2 investigation. These investigations are complex and involve several safety issues requiring in-depth analysis. Class 2 investigations, which frequently result in recommendations, are generally completed within 600 days. For more information, see the Policy on Occurrence Classification.

TSB investigation process

There are 3 phases to a TSB investigation

  1. Field phase: a team of investigators examines the occurrence site and wreckage, interviews witnesses and collects pertinent information.
  2. Examination and analysis phase: the TSB reviews pertinent records, tests components of the wreckage in the lab, determines the sequence of events and identifies safety deficiencies. When safety deficiencies are suspected or confirmed, the TSB advises the appropriate authority without waiting until publication of the final report.
  3. Report phase: a confidential draft report is approved by the Board and sent to persons and corporations who are directly concerned by the report. They then have the opportunity to dispute or correct information they believe to be incorrect. The Board considers all representations before approving the final report, which is subsequently released to the public.

For more information, see our Investigation process page.

The TSB is an independent agency that investigates air, marine, pipeline, and rail transportation occurrences. Its sole aim is the advancement of transportation safety. It is not the function of the Board to assign fault or determine civil or criminal liability.