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Rail transportation safety investigation R21H0114

The TSB has completed this investigation. The report was published on 13 March 2024.

Table of contents

Non–main-track train collision and derailment

Canadian National Railway Company
Intermodal train Z14921-02 and industrial switching assignment L53231-02
Mile 113.44, Kingston Subdivision
Prescott, Ontario

View final report

The occurrence

The accident

On 02 September 2021 at about 1028,Footnote 1 Canadian National Railway Company (CN) intermodal train Z14921-02 (train 149) was proceeding westward on the north main track of the Kingston Subdivision where a hand-operated switch provides access to an industrial spur track in the town of Prescott, Ontario.

Train 149 was to pass by the switch and continue on the north main track to Toronto, Ontario. However, having received permission from the rail traffic controller (RTC) to enter the north main track in accordance with Rule 568 of the Canadian Rail Operating Rules (CROR), the crew of CN train L53231-02 (train 532), an industrial switching assignment, had reversed the switch to track KE01 of the industrial spur.

The RTC did not obtain the required location report from the crew on train 149. Therefore, he did not know the train’s exact location in relation to the switch. When the RTC received the request from train 532 to enter the north main track, he developed a mental model that train 149 had already gone by the switch and he therefore issued the CROR Rule 568 permission to train 532. At that time, the RTC’s workload was complex, and his attention was diverted to other competing tasks.

Approaching the switch, the crew members on train 149 realized that it was lined against them and placed the train into emergency, but the train was unable to stop. Train 149 entered the spur track where it collided head-on with train 532at approximately 37 mph.

As a result of the collision, the 4 locomotives (2 on each train) derailed and sustained significant impact damage. The fuel tank on the lead locomotive of train 149 was punctured and released diesel fuel, but the fuel did not ignite. Fourteen intermodal car bodies loaded with double-stack containers also derailed along with 2 stationary cars on the spur track. There was significant damage to the north main track, the south main track, and 2 of the tracks in the industrial spur; in total, approximately 1000 feet of track was destroyed.

Two crew members sustained minor injuries, and 1 crew member was admitted to hospital with serious injuries.

Results of mandatory post-accident alcohol testing of the rail traffic controller

Under CN’s Policy to Prevent Workplace Alcohol and Drug Problems, employees have to submit to mandatory breath alcohol testing following an accident. About 2 hours after the accident, the RTC submitted to the mandatory breath alcohol test, which was conducted by DriverCheck Inc., a third-party provider of workplace medical testing and assessments. A breath alcohol test indicated a breath alcohol concentration (BrAC) of 0.023 g/210L. Seventeen minutes later, a confirmation breath alcohol test was completed and indicated a BrAC of 0.019 g/210L. The results were reviewed by the chief medical review officer of DriverCheck Inc, who indicated that the RTC’s extrapolated blood alcohol concentration (BAC) was estimated to have ranged from 0.064% to 0.109% at the start of his shift, and from 0.044% to 0.069% at the time of the accident. The report produced by the chief medical review officer indicated that the RTC was either drinking alcohol at the beginning of his shift or had significant alcohol intake the early morning of or the night before work.

The RTC’s performance and level of attention were likely affected by the persistent effects of alcohol consumption.

Safety concern

Consumption of alcohol before assuming safety-critical duties

Alcohol affects human performance due to its negative effects on psychomotor skills and cognitive functions such as decision making, attention, and reasoning. Alcohol has a particularly serious effect on information processing and working memory, and even relatively low doses of alcohol can lead to reduced performance. Although psychomotor skills recover when the BAC decreases, cognitive performance can still be negatively affected.

The Railway Safety Act and regulations made under the Act do not prescribe a time period prohibiting the consumption of alcohol before assuming duties. Therefore, individuals are expected to self-assess and determine if the effects of alcohol have sufficiently diminished to be fit for duty. As the BAC of individuals decreases, there is a risk that they may not accurately self-assess, and therefore could subjectively perceive that they have recovered despite the effects of alcohol on cognitive performance persisting. In comparison, the Canadian Aviation Regulations stipulate, in part, that no person shall act as a crew member of an aircraft within 12 hours after consuming an alcoholic beverage or as an air traffic controller or a flight service specialist within 8 hours after consuming alcohol. These time prohibition periods allow for the elimination of alcohol and, as such, they reduce the risk that a person will assume safety-critical duties while under its influence.

Alcohol impairment involving employees in safety-critical positions can have significant adverse outcomes, affecting the safety of crews, passengers, and the environment.

Therefore, given that no time period prohibiting the consumption of alcohol by railway employees in safety-critical positions in Canada is required, the Board is concerned that such employees could perform their duties while under the influence of alcohol.

Media materials

News releases


TSB highlights risks associated with alcohol consumption before assuming safety-critical duties following 2021 head-on train collision in Prescott, Ontario
Read the news release

Deployment notice


TSB deploys investigators to train collision in Prescott, Ontario

Ottawa, Ontario, 2 September 2021 — The Transportation Safety Board of Canada (TSB) is deploying a team of investigators following a collision between two CN trains in Prescott, Ontario. The TSB is gathering information and assessing the occurrence.

Investigation information

Map showing the location of the occurrence


Photo of Jerry Berriault

Mr. Berriault has been with the Transportation Safety Board of Canada (TSB) since 2007. He is a senior regional investigator, Central Region, based out of the Winnipeg, Manitoba, office.

Among other responsibilities, he has been the Investigator-in-charge of eight rail accident investigations and served as a team member in a number of other investigations throughout Canada, providing operational and technical expertise.

Before joining the TSB, Mr. Berriault held numerous positions with Canadian National Railway (CN) from 1980 until 2007, including superintendent of operations. While at CN, he gained extensive knowledge of all aspects of train operations, including both the mechanical and engineering functions.

Class of investigation

This is a class 3 investigation. These investigations analyze a small number of safety issues, and may result in recommendations. Class 3 investigations are generally completed within 450 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.