Associated links (R15H0021)
Kathy Fox
Chair, Transportation Safety Board of Canada
and
Rob Johnston
Manager, Central regional operations, Transportation Safety Board of Canada
Sudbury, Ontario, 3 August 2017
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Kathy Fox
Good morning,
On March 7th 2015, a CN unit freight train loaded with petroleum crude oil was travelling at 43 mph when it derailed 39 tank cars near the town of Gogama, Ontario. As a result of the derailment, about 2.6 million litres of product were released, ignited, caused explosions and contaminated the nearby Makami River. A CN rail bridge over the river and about 1000 feet of track were destroyed. There was no evacuation and no injuries.
This was the third significant CN freight train derailment in a three week span in early 2015 along the Ruel Subdivision in Northern Ontario. A few months ago, the TSB released its investigation into the first accident which occurred at Gladwick, Ontario, about 25 miles northwest of Gogama.
While there were similarities between the 2 accidents, the exact circumstances surrounding them were different as we will outline today.
Railways regularly inspect track throughout their network to check for defects identified under the Track Safety Rules. They also inspect for other track surface conditions which are not identified under the Track Safety Rules but are managed by the railway and can be used as leading indicators to predict emerging track issues.
Transport Canada does not regularly collect or review data on these leading indicators when planning its periodic targeted track inspections.
Today, the TSB is recommending that Transport Canada acquire leading indicator information on rail surface conditions, and incorporate it into its risk-based planning approach to better focus its track inspections.
I'll talk more about that and what that means in just a few minutes. But first I'll turn things over to the Regional Manager, Rob Johnston. He'll walk you through the sequence of events, explaining the specifics of how—and why—this derailment occurred.
Rob Johnston
Thank you, Kathy.
When repairing a broken rail, a section containing the rail break is cut out of the track. A dye penetrant test, which is a non-destructive method of checking for cracks which may not be visible to the naked eye, is performed on the cut ends of the rail left in service. If no cracks are found, a "plug rail" of similar dimension is installed and secured to the track with joint bars at either end of the plug.
Three days prior to the accident, a track maintenance employee repaired a break in the south rail by installing a plug rail. During the repair, the south rail was cut and the employee visually inspected the exposed rail ends but missed an internal defect, called a vertical split head . The defect was likely present but not visible, and remained in the rail head.
Although required by CN, a dye penetrant test was not performed. While aware of the test, the employee had never performed one or seen it performed.
CN's training did not highlight the importance of the test and did not provide opportunities for practical hands-on training.
When the repair was completed, the rail head ends within the joint were mismatched in height. To ease the transition between the rail heads, the plug rail head end was subjected to grinding.
However the grinding was insufficient and a mismatch between the two rail heads remained. Given the state of the repair, a track slow order should have been put in place to reduce train speed, but none was applied.
Because CN's procedures for rail testing and installing a plug rail were located in multiple manuals, they were not easy to find. There was also no guidance related to rail head grinding during such repairs and there was no checklist to outline the steps required to complete the repair.
Once the track was returned to service, the mismatched joint was subjected to continuous pounding from freight car wheels as they traversed the repair. Three days later, the defect within the rail failed, the rail broke away under the train and the 6th to 44th tank cars derailed.
In this accident, the derailed cars were built to a higher standard than the legacy DOT 111 tank cars involved in the Lac-Mégantic tragedy of 2013. While these newer cars, known as CPC-1232, feature tougher steel and half-head shields, they do not all have jackets or thermal protection. Consequently, we found similar tank car performance issues as in the Lac-Mégantic and Gladwick accidents.
As we all know, crude oil can be highly volatile and environmentally hazardous, and in this case, it led to a significant post-crash fire and ongoing environmental concerns.
Since the accident, CN has:
- Improved training for dye penetrant testing;
- Added a requirement that a track slow order be applied if a dye penetrant test is not performed;
- Implemented checklists for repairing a broken rail and performing a dye penetrant test; and
- Implemented an environmental plan to restore the site while monitoring continues.
Kathy will now talk about what more is needed to improve rail safety.
Kathy Fox
Thank you, Rob.
While the specifics of what caused the derailment at Gogama were different from those in Gladwick, there were also similarities.
First, there is a direct correlation between train speed and the severity of the outcome. That's why the TSB continues to be concerned that some speed limits may be too high, particularly for unit trains carrying flammable liquids. The Gladwick and Gogama derailments both occurred at a speed below the maximum permitted track speed.
As part of the Gladwick investigation, the TSB recommended that Transport Canada study all factors that increase the severity of derailments involving dangerous goods—including speed— then develop mitigating strategies, and amend the rules accordingly.
Secondly, although Transport Canada implemented an accelerated phase-out of the "legacy" DOT 111 tank cars, the CPC 1232 tank cars will not be fully phased out until 2025. Until then, less-robust tank cars will continue to be allowed to transport Class 3 flammable liquids.
And finally, there were also issues with track maintenance and railway personnel training.
The difference is that in this investigation we identified a systemic gap in Transport Canada's planning process for targeted regulatory track inspections.
To select subdivisions for its inspections, Transport Canada uses a risk-based planning approach that considers various factors to identify areas of concern. Most of the factors considered by Transport Canada during the planning process are what we call lagging indicators, such as the number of accidents, broken rails or track defects that required repair under the Track Safety Rules. Lagging indicators are events that have already occurred.
On the other hand, leading indicators, such as localized surface collapse, rail end batter and crushed heads, are emerging rail surface conditions that can indicate track deterioration, but are not considered to be defects.
Track defect information is required to be reported to Transport Canada while rail surface condition information is not provided and rarely requested by the regulator. Consequently, these conditions are not always considered as part of Transport Canada's planning.
By integrating rail surface condition data, the planning process may more clearly identify areas of potential track deterioration and the targeted track inspections can be better focused to reduce risk in the rail transportation system. Therefore, the TSB recommends that Transport Canada acquire rail surface condition data, including information on localized surface collapse, rail end batter and crushed heads, and incorporate it into its planning for targeted regulatory track inspections.
This accident occurred on an isolated stretch of rail in Northern Ontario. While no one was injured, environmental concerns remain. As long as issues related to train speed, tank car crashworthiness, track maintenance, and railway personnel training remain, the transportation of flammable liquids by rail will continue to pose a risk to people, property, and the environment.