Rail car inspection deficiencies noted
FEDERAL — Federal investigators have identified deficiencies regarding how equipment was
attached to tank car shells, as part of an investigation into a dangerous goods derailment
on February 9, 2010.
Just before 6 am, a non-pressure dangerous goods tank car broke into two sections and
derailed during switching operations at the Canadian National Railway’s MacMillan Yard in
Toronto, notes a report by the Ottawa-area Transportation Safety Board of Canada (TSB).
When the car failed, a load of approximately 57,000 litres of liquid ferric sulphate was
released along the roadway and adjacent tracks.
Three other cars were damaged in the derailment, but there were no injuries.
In its report released November 17, TSB investigators identified safety deficiencies
regarding equipment attachment to tank cars, the properties of materials used to construct
non-pressure tank cars before 1990, and inspection standards and methods used during tank
car requalification.
The report notes there are approximately 82,000 railway non-pressure tank cars throughout
North America that were built before September, 1990 and share similar material and design
features to the car that failed.
Since that date, the Association of American Railroads M-1002 standard has required brackets
to be secured to tank car reinforcement pads (re-pads) to provide localized reinforcement
and skid protection for the shell, and shear protection for equipment welded to them.
However, the standard does not require cars built before September, 1990 to be frequently
inspected or retrofitted with re-pads.
“The lack of harmonization of tank car standards represents compliance and enforcement
challenges that can, at times, be confusing and present a safety risk,” the report states.
“Without consistent, harmonized standards requiring the use of re-pads for any air brake
equipment support attachment, regardless of car built date, there is an increased risk of
tank car failure for non-pressure, non-jacketed tank cars built prior to September, 1990.”
The TSB reports that a reliance on visual inspection alone for conducting structural
integrity inspections during tank car qualifications presents a risk that cracks in
equipment attached to rail cars may not be consistently detected.
Since 2005, the country has witnessed four catastrophic failures of non-pressure tank cars.
In each case, material properties of the non-normalized steel used for manufacturing the
non-pressure cars met specifications in place at the time of construction. Despite that,
the cars failed from small pre-existing fatigue cracks at a temperature of -9 degrees
Celsius or colder, the report adds.
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