Assessment of the response to Rail Safety Recommendation R02-02 - R99T0256
The Department of Transport, in conjunction with the tank car owners, review the existing inspection and maintenance program for thermal protection of tank cars already in service, and ensure that their thermal protection systems confer acceptable thermal resistance to reduce the risk of the premature release of dangerous goods in a fire.
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Rail transportation safety investigation report
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| Date the recommendation was issued |
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| Date of the latest response |
June 2004
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| Date of the latest assessment |
May 2005
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| Rating of the latest response |
Fully Satisfactory
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| File status |
Closed
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Summary of the occurrence
At 1311 eastern daylight time on 23 September 1999, Canadian National freight train M304-41-21, destined for Toronto, Ontario, derailed 26 cars near the north siding switch at Mowat, near Britt, Ontario. The derailed equipment included 14 residue tank cars last containing liquefied petroleum gas (LPG), 1 tank car loaded with LPG and 3 tank cars loaded with anhydrous ammonia. The loaded LPG car and one anhydrous ammonia car were breached, each releasing product and igniting, resulting in several fires. At 1348, the loaded car of LPG exploded, projecting pieces of its tank and jacket in all directions. Approximately 127 000 pounds of LPG and 158 000 pounds of anhydrous ammonia were released. All the LPG and a large amount of the anhydrous ammonia were consumed by fire. The train crew was not injured; however, an Ontario Provincial Police officer, a local woodcutter, and two firemen suffered minor injuries as a result of contact with ammonia vapours.
Rationale for the recommendation
Tank cars are subject to a re-qualification inspection which includes the thermal protection; however, the standards do not contain requirements on methods of inspection, nor the relationship between thermal protection degradation, such as shifts or voids in the insulation, and the actual thermal resistance of the cars. As the presence of fire is frequent in a derailment, there is a risk to the public that hazardous products may be prematurely released to the atmosphere in the time-critical initial stages of an emergency response, before proper isolation and evacuation procedures can be implemented. Therefore, the Board recommended that:
The Department of Transport, in conjunction with the tank car owners, review the existing inspection and maintenance program for thermal protection of tank cars already in service, and ensure that their thermal protection systems confer acceptable thermal resistance to reduce the risk of the premature release of dangerous goods in a fire.
TSB Recommendation R02-02
Previous responses and assessments
January 2003: Board Assessment of the Response to R02-02
The Board recommended a review of existing inspection and maintenance programs to ensure the performance of thermally protected cars. TC has taken many positive steps to fulfill the spirit of the recommendation. The response includes a number of ongoing initiatives, e.g. audits of shop facilities, participation with FRA in an AAR Task Force of the Tank Car Committee, and use of thermography to help identify thermal voids. Some of these initiatives predate the date of the occurrence.
The more recent research work, and the development of a tool to allow employees to scientifically determine the maximum acceptable deterioration of thermal protection shows promise. Such a tool will allow persons performing re-qualification inspections to quantify the relationship between thermal voids and degradation, a key to understanding whether a tank car that has been in service a number of years, can continue to provide adequate thermal resistance, to prevent the premature release of dangerous goods in a fire.
Improved testing procedures, stipulated methods of inspection and acceptable test results, when combined with improved technology and widespread industry participation, will address the identified safety deficiency. In consideration of the ongoing initiatives in that regard, the anticipation of this new technology's introduction, and the participation of the AAR Tank Car Committee, the response to Recommendation R02-02 is assessed as being "Satisfactory intent".
Latest response and assessment
June 2004: Additional Response to R02-02
TC participated in the FRA - AAR Task Force in audits of tank car facilities. TC has been performing thermography inspections to help identify thermal voids, and as a result has recently removed non-conforming tank cars from service for repair or scrapping. TC has purchased thermographic equipment for its field forces in Canada and provided training to some of its inspectors for this purpose. TC has also provided training to US DOT FRA inspectors as well
May 2005: Board Reassessment of Response to Recommendation R02-02
In consideration that TC has implemented the use of the new technology and provided training for field forces in Canada and the USA the Board reassesses the response to Recommendation R02-02 as being "Fully Satisfactory".
File status
Next TSB Action
File is closed.