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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

The train

The derailment

The 53rd car

Progress to date

While on site, the team:

Following completion of site work, the team:

Next steps

The next steps of the investigation include the following:

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):

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.