Backgrounder

Safety communications for TSB investigation (R15H0021) into the March 2015 derailment and fire of a Canadian National crude oil train near Gogama, Ontario

The occurrence

On 07 March 2015, a Canadian National Railway (CN) crude oil unit train was proceeding eastward at about 43 mph on CN's Ruel Subdivision when it experienced a train-initiated emergency brake application at Mile 88.70, near Gogama, Ontario. A subsequent inspection determined that the 6th to the 44th cars (39 cars in total) had derailed. As a result of the derailment, about 2.6 million litres of petroleum crude oil (UN1267) were released to atmosphere, water, or surface. The released product ignited and caused explosions, and some product entered the nearby Makami River. A CN bridge over the Makami River (at Mile 88.70) and about 1000 feet of track were destroyed. There was no evacuation, and there were no injuries.

TSB recommendations

The Canadian Transportation Accident Investigation and Safety Board Act specifically provides for the Board to make recommendations to address systemic safety deficiencies posing significant risks to the transportation system and, therefore, warranting the attention of regulators and industry. Under the Act, federal ministers must formally respond to TSB recommendations within 90 days and explain how they have addressed or will address the safety deficiencies.

Recommendation made on 3 August 2017

Rail flaw technology to detect localized surface collapse (LSC), rail-end batter (REB), or crushed heads (CH) rail surface conditions is relatively new. Although these rail surface conditions are leading indicators of deteriorating rail, the Rules Respecting Track Safety (TSR) contain no guidance or condemning criteria for them. If not properly addressed, REBs can result in joint failure and derailment. LSCs, REBs, and CHs can result in high contact stresses and can lead to or accelerate the development of other rail defects such as a transverse detail defect or a vertical split head which can fail rapidly and result in a derailment.

Information for these emerging rail surface conditions is not generally provided to Transport Canada (TC), specifically considered as part of TC's risk-based approach, or reviewed by TC for any increase in the number of these conditions.

With more complete LSC, REB, and CH data, TC's risk-based approach for planning targeted regulatory track inspections can be augmented using this valuable information relating to leading indicators of degrading track conditions. The absence of this information represents a gap in TC's planning process, which can result in targeted inspections that are not well focused. Therefore the Board recommends that:

The Department of Transport acquire rail surface condition data, including information on localized surface collapse, rail end batter and crushed heads, and incorporate it into its risk-based planning approach for targeted regulatory track inspections.
TSB Recommendation R17-02

Recommendation made on 16 February 2017

As part of the TSB investigation into the February 2015 Gladwick derailment, the Board issued a recommendation relating to the factors that increase the severity of derailments involving dangerous goods, including train speeds for various train risk profiles.

The Gladwick investigation report indicated that TC had recognized the role that train speed and train risk profile play in severity of the outcome of a derailment, and had put some measures in place to limit the speed of "key trains" under certain conditions. The TC-approved Rules Respecting Key Trains and Key Routes restrict "key trains" to a maximum speed of 40 mph within the core and secondary core of CMAs. Although the restrictions contained in the rules were a step forward at the time issued, the current maximum speed of 40 mph was selected without being validated by any engineering analysis. Therefore, the Board recommended that:

The Department of Transport conduct a study on the factors that increase the severity of the outcomes for derailments involving dangerous goods, identify appropriate mitigating strategies including train speeds for various train risk profiles and amend the Rules Respecting Key Trains and Key Routes accordingly.
TSB Recommendation R17-01

TSB assessment of Transport Canada's response to recommendation R17-01 (July 2017)

Transport Canada has acknowledged this recommendation.

TC will conduct a literature review of existing studies on the factors affecting the severity of derailments involving dangerous goods. TC will then assess the results of the literature review to determine if additional scientific and engineering analysis would be meaningful to further understand the derailment severity factors. This assessment will allow TC to determine if changes should be made to the Rules Respecting Key Trains and Key Routes.

The Board notes that, although no timeline has been proposed, TC has committed to conducting a literature review of existing studies and to assessing the results of the review. However, beyond this commitment, there are no explicit plans for TC to conduct its own study on derailment severity factors.

Therefore, the Board assesses the response to Recommendation R17-01 to be Satisfactory in Part.

Glossary

Rail end batter (REB) occurs at a rail joint when the ends of the rail heads within the joint are mismatched and/or the gap between the rail ends is too large. REB is indicative of degrading joint support that can result in excessive joint movement which can be further degraded by mechanical interaction from repetitive wheel loadings. If not properly addressed in the field, REBs can ultimately result in joint failure and derailment.

A localized surface collapse (LSC) is characterized by plastic metal flow, leading to the flattening out and deformation of the rail head above the plane of the rail head/web fillet. LSCs are normally caused by mechanical interactions from repetitive wheel loadings.

A crushed head (CH) deformation of the rail head extends to below the plane of the rail head/web fillet. CHs are normally caused by mechanical interaction from repetitive wheel loadings.