Rail transportation safety investigation R19T0107

Updated in November 2020 : This investigation is in the analysis and report production phase.

Table of contents

Main-track derailment

Canadian National Railway Company
Strathroy Subdivision
Sarnia, Ontario

The occurrence

On , at around 0420 Eastern Daylight Time (EDT), a westbound Canadian National Railway Company (CN) freight train derailed on the Canadian side of CN’s St. Clair Tunnel between Sarnia, Ontario, and Port Huron, Michigan, United States. During the site examination, it was determined that 45 cars and the mid-train remote locomotive (46 rolling stock in total between lines 51Footnote 1 and 98) had derailed. There were no injuries. One dangerous goods car loaded with sulphuric acid was breached and released most of its load. The TSB is investigating.

What we know based on initial examinations

Sequence of events

  • On 28 June 2019, westbound CN freight train M38331-27 was a key train operating on the CN Strathroy Subdivision, which is a key route.
  • At about 0402 EDT, the train, operated by a three-person crew (locomotive engineer, conductor, and brakeman) departed from Sarnia enroute to Port Huron.
  • The train proceeded through the Paul M. Tellier Tunnel under the St. Clair River. The tunnel crosses the international border between Canada and the U.S., connecting Sarnia and Port Huron.
  • At approximately 0420, while travelling at 44 miles per hour in the tunnel, the train experienced a train-initiated emergency brake application, with the head-end locomotive at Mile 61.19 of the Strathroy Subdivision.
  • The head-end of the train came to rest outside of the tunnel at Mile 61.46, about 1670 feet west of the tunnel portal in Port Huron.

The train

  • The train consisted of two head-end locomotives, one mid-train distributed power (DP) remote locomotive located between cars 81 and 82, and a total of 140 cars. Of the 140 cars, 125 were loaded cars, 12 were empty cars, and three were residue cars.
  • The train was 9541 feet long and weighed 15 674 tons.

The derailment

  • A total of 46 rolling stock between lines 51–98 inclusive derailed and came to rest on both sides of the international border inside the tunnel.
  • Examination of the locomotive event recorder data by both the TSB and the U.S. National Transportation Safety Board (NTSB) determined that the initial point of derailment occurred in Canada.
  • The derailed cars included dangerous goods tank car UTLX 95205, which was loaded with sulphuric acid. During the derailment, that car was breached and released most of its load (about 12 000 U.S. gallons) in the tunnel.
  • The trailing end of the 51st car and all the wheels of the 52nd car were derailed. Behind the 52nd car, the south rail had rolled, and there was a separation of 696 feet leading up to the A-end of the 53rd car.

The 53rd car

  • The A-end of the 53rd car (bathtub gondola DJJX 30478) appeared to have collapsed. It exhibited extensive damage and had a broken knuckle. The fracture surface of the knuckle displayed brittle fracture characteristics, but had no visible pre-existing defects.
  • The A-end of car 53 had skewed diagonally, and the south rail had rolled to the south side of the tunnel.
  • This car was likely the first car to derail.

Progress to date

While on site, the team:

  • collected data from the accident site,
  • collected electronic data from the locomotives,
  • conducted interviews,
  • examined and photographed the wreckage,
  • identified components for further examination by the TSB in collaboration with the National Research Council (NRC) Canada,

Following completion of site work, the team:

  • conducted compression testing of three cars of similar construction, age, and condition to car DJJX 30478, in Ottawa, in collaboration with the NRC,
  • developed dynamic simulations to evaluate in-train forces, train handling, and train marshaling, and
  • reviewed company operational policies and procedures in conjunction with regulatory requirements.

Next steps

The next steps of the investigation include the following:

  • Reviewing regulations and life-cycle guidelines for similarly built bathtub gondola cars of similar age
  • Examining rail car maintenance records
  • Conducting additional interviews as required
  • Completing the analysis and report production phases of the investigation

Investigation teamwork

The Investigator-in-Charge, Rob Johnston, is being assisted in this investigation by TSB investigators with backgrounds in rail standards, rolling stock, track, operations, and engineering.

Representatives from Transport Canada, the NTSB, David J. Joseph Company (car owner) and CN are providing assistance with this investigation.

We would also like to recognize the contributions of the U.S. Federal Railroad Administration, and the U.S. Environmental Protection Agency to this investigation.

Identification of safety deficiencies

Investigations are complex, and the TSB takes the time needed to complete a thorough investigation. However, should the investigation team uncover safety deficiencies that present an immediate risk, the Board will communicate them without delay.

Safety communications

Given the significant consequences of the train derailment involving dangerous goods in the St. Clair Tunnel, the TSB issued four rail safety advisory letters (RSAs):

  • RSA 08/19, issued 19 August 2019, advises Transport Canada to ensure that railways have specific instructions or guidance in their emergency procedures for conducting train inspections following a derailment in a tunnel involving dangerous goods.
  • RSA 09/19, issued 16 September 2019, advises Transport Canada and the US Federal Railroad Administration to ensure that railways and car owners have procedures in place to identify, inspect, and repair (as required) bathtub gondola cars that are equipped with stub sills, particularly those being used in scrap iron and steel service, which were constructed in the late 1970s and early 1980s.
  • RSA 06/20, issued 11 September 2020, advises Transport Canada to ensure that all railways have adequate practices in place to effectively manage in-train forces.  
  • RSA 07/20, issued 11 September 2020, advises Transport Canada and the US Federal Railroad Administration to ensure that all bathtub gondola cars built by Berwick Forge and that operate in North America, are identified, located and examined to ensure continued safe railway operations.

Media materials

News releases


Investigation Update Notice: June 2019 train derailment in Sarnia, Ontario
Read the news release


The Transportation Safety Board of Canada to conduct the investigation into the train derailment in the St. Clair Tunnel between Sarnia, Ontario, and Port Huron, Michigan
Read the news release


The TSB and NTSB are assessing CN train derailment in the St. Clair Tunnel between Sarnia, Ontario, and Port Huron, Michigan
Read the news release

Deployment notice


TSB deploys a team of investigators to the site of a train derailment in Sarnia, Ontario

The Transportation Safety Board of Canada (TSB) is deploying a team of investigators to the site of a Canadian National Railway train derailment in the Sarnia tunnel in Sarnia, Ontario. The TSB will gather information and assess the occurrence.

Investigation information

Map showing the location of the occurrence


Photo of Rob Johnston

Mr. Rob Johnston has been with the Transportation Safety Board of Canada (TSB) since 2001. He was Senior Regional Investigator in Winnipeg until 2004, when he assumed the position of Senior Investigator, Standards and Training Officer at TSB Head Office in Gatineau, Quebec. He became Manager of Central Regional Operations in November 2009, and served as Acting Director of Investigations - Rail/Pipeline for 9 months in 2010– 2011.

He now manages a staff of 6 rail/pipeline investigators in Winnipeg, Toronto, and Ottawa, and is responsible for all activities related to rail investigations in TSB’s Central Region, which extends from Cornwall, Ontario, to near the Alberta–Saskatchewan border.

During his time at the TSB, Mr. Johnston has been involved in over 100 TSB accident investigations including 14 major investigations as either an Investigator-in-Charge or as an investigation team member providing technical expertise.

Before joining the TSB, Mr. Johnston worked for Canadian Pacific Railway in Winnipeg from 1984 until 2001, where, as a member of the Train Accident Prevention group, he acquired an extensive background in mechanical operations, failure analysis, and dangerous goods.


  Download high-resolution photos from the TSB Flickr page.

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.

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