7 September 2005
The Transportation Safety Board of Canada Completes its Investigation into a Derailment Involving Anhydrous Ammonia Leak in Estevan, Saskatchewan
The Transportation Safety Board of
Canada (TSB) today released its final report (R04W0148) into the Canadian
Pacific Railway (CPR) derailment of 8 Aug 2004 in Estevan, Saskatchewan.
Following the derailment, 150 people were evacuated from their homes for two
days due to the release of a small amount of anhydrous ammonia.
The TSB investigation revealed that defects on a freight car truck
restricted it from properly turning through the turnout curve. As the car
negotiated the curve, these defects combined to induce higher-than-usual truck-
side lateral forces into the south rail of the curve. The derailment occurred
when an 85-pound rail section could not sustain the increased lateral load and
rolled out from beneath the train. The report also revealed that the turnout
curve had not been maintained in accordance with CPR standards and identified
that the current method of performing mechanical safety inspections presents a
risk that defects, similar to those on the defective freight car, may not be
consistently detected. It was also noted that, at the time of the accident,
the timely response and evacuation of the inhabitants in the surrounding area
minimized the risk of exposure to dangerous goods.
Rob Johnston, Investigator-in-Charge of this accident, stated that, "in
response to the TSB investigation, significant safety action has taken place
to make rail transportation safer in Canada". The report states that the rail
industry is planning to install new automated inspection equipment that will
detect the type of truck deficiencies that were present on the derailed car.
The report further reveals that CPR has since developed a number of measures
to illustrate what to look for when inspecting freight car centre plates and
side bearings. CPR also replaced all 85-pound rail beyond the Bromhead turnout
curve with 100-pound rail sections, set on double-shouldered tie plates
secured with three spikes per plate.
On 8 Aug 2004 at 1341 central standard time, CPR freight train 494-05
was reversing onto the Bromhead Subdivision when it derailed six cars at Mile
0.01 within the city of Estevan, Saskatchewan. Five of the six derailed cars
were pressurized tank cars containing anhydrous ammonia. One tank car
sustained a fracture in the tank head, releasing a small amount of product to
atmosphere. As a precaution, about 150 people within a three-block radius of
the derailment site were evacuated for two days. There were no injuries.
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