Communiqués

TSB # R 04/2001

(Thamesville, Ontario) 05 April 2001 - The Transportation Safety Board of Canada (TSB) investigation report into the derailment involving VIA Rail Canada Inc. (VIA) train No. 74 at Thamesville, Ontario, on 23 April 1999 was released today.

The investigation found that, as the eastbound train on the north main track approached reversed crossover switches, the locomotive crew put the train brakes in emergency, sent a distress message to oncoming VIA train No. 71 (with about 110 passengers and crew on board) proceeding westward on the south main track, and shut down the engine. All this was done in a matter of seconds before the locomotive was forced onto the south main track, derailed, rolled over, and slammed into stationary hopper cars carrying ammonium nitrate. Both locomotive crew members lost their lives in this accident.

One of the conclusions drawn by the TSB was that the quick actions of the two locomotive crew members on VIA train No. 74 likely averted a greater disaster when their train derailed and collided with hopper cars standing on a siding.

The actions of the locomotive crew members probably prevented a secondary collision with the approaching westbound passenger train. Shutting down the engine also removed an ignition source that could have ignited the dangerous good, ammonium nitrate, which spilled from the hopper cars that were struck on the adjacent siding.

Seventy-seven of the 186 passengers and crew on board VIA train No. 74 were treated in hospital. Four people were admitted with serious injuries. Numerous others received first aid on site. The accident at Mile 46.7 of the Canadian National (CN) Chatham Subdivision derailed the locomotive, all four cars of VIA train No. 74, and four of the stationary hopper cars on the adjacent siding.

As a result of this accident, the TSB identified a number of safety deficiencies. Specifically, the Board is concerned about the level of safety defences associated with the Occupancy Control System (OCS) method of train control, especially in areas where there are no signals to provide information to the train crew about the condition of the track ahead ("dark territory"). This means that train crews are not always provided with sufficient warning of reversed main track switches. As well, the Board is concerned about the storage of dangerous goods adjacent to main tracks for extended periods of time.

Both the railways and the regulator have taken measures to address deficiencies identified in this investigation. The Board believes that more needs to be done and, in its final report, has issued three rail safety recommendations dealing with the need to improve the safety of trains operating under the OCS and to review the storage of dangerous goods adjacent to main tracks.

The Transportation Safety Board of Canada is an independent agency operating under its own Act of Parliament. 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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Backgrounder

(05 April 2001) - In the 20 months after the accident at Thamesville (to December 2000), there were 14 occurrences reported to the TSB where trains unexpectedly encountered reversed main track switches in OCS dark territory; 4 of those involved passenger trains. The overall occurrence data indicate that, despite the ongoing safety action by the regulator and the industry, in all types of territory, reportable occurrences of this nature have continued to average around 10 annually. Further, some of these occurrences continue to involve passenger trains, where the potential for loss of life is much greater.

While significant safety action has been taken, additional improvements are not a certainty. Although the initiatives of Transport Canada (TC) and the railway industry should result in significant safety improvements, the long-term continuation of some of these improvements is uncertain.

The Board notes that the conditions of TC's Emergency Directive, for operations in OCS territory, may not continue beyond the six-month period dictated in the Directive. The Board believes that a serious situation still exists, with a continuing probability of passenger trains encountering unanticipated reversed main track switches, albeit at lower speeds. The Board has recommended that:

• The Department of Transport require the development of additional permanent system defences that permit a means to help ensure safety when trains approach main track switches in Occupancy Control System outside Automatic Block Signal System territory. [R01-01]

This investigation determined that, in OCS outside Automatic Block Signal System (ABS), the existing safeguards were inadequate to prevent the unauthorized reversed main track switches from leading to the occurrence. The Board has expressed this concern and has identified previously that an overreliance on procedures and rules in the operation of safety critical systems is an undesirable situation. The Board has been advocating the development of safety strategies, where multiple layers of defences are used to improve error tolerance, where necessary. The Board believes that, when the effect of a single error on a safety critical system can lead to the derailment of a passenger train at high speed, the error tolerance of that system is inadequate.

Unauthorized reversed main track switches are most often the result of inadvertent errors by railway employees. Past safety actions relating to unauthorized reversed main track switches have focussed primarily on eliminating errors through improved procedural compliance. The speed restrictions imposed through TC's Emergency Directive, although temporary, indicate an acknowledgement of the inevitability of some level of human error with respect to the handling of main track switches. The Board believes that this is a necessary first step towards understanding the effects of errors on a safety critical system and towards developing mitigating strategies and has recommended that:

• The Department of Transport, the Railway Association of Canada and provincial authorities responsible for train operations review the system design specifications for computer-assisted and non-computer-assisted Occupancy Control System in Canada to ensure all components of these systems are designed with sufficient regard to human error. [R01-02]

At Thamesville, the storage of certain dangerous goods in rail cars for prolonged periods of time, adjacent to main tracks where train speed is not restricted and passenger trains also operate, created an unacceptable level of risk for persons, property and the environment. Although it is rare that a derailed train would come into contact with stored dangerous goods, the Board believes that the risks posed, particularly within municipal areas and when passenger trains are involved, are unacceptable.

TC's initiative to redefine the term "in transport" in the upcoming clear-language version of the Transportation of Dangerous Goods Regulations, while useful, is unlikely to have an effect on the storage of dangerous goods at places like Thamesville. The Board believes that the proposed new wording does not clarify when a shipment is considered to have been delivered to destination and has recommended that:

• The Department of Transport review the current regulatory framework and industry policy to help ensure that an adequate level of safety is maintained regarding the storage of dangerous goods within the rail transportation system and during the transition of shipments of dangerous goods to or from the rail transportation system. [R01-03]

The TSB investigation on this occurrence found strong indications that recent improvements in the areas of passenger safety and emergency preparedness had reduced the risks to which passengers were exposed and contributed to a safe and efficient evacuation of the train. However, a number of passenger safety-related hazards, identified and reported on in previous investigations, were also found; i.e., an unsecured metal tool box and unrestrained baggage in end baggage compartments. Although the Board recognizes that legitimate safety priorities of the railway industry and regulator may preclude the prompt mitigation of all known risks, valuable opportunities for passenger safety improvements were delayed when known conditions were not quickly dealt with. The Board is concerned that, in some circumstances, industry and regulatory safety programs have not resulted in the elimination of some passenger safety hazards in a timely fashion.