The Transportation Safety Board of Canada is recommending that Transport Canada (TC) incorporate predictive data on rail surface conditions to help with targeted regulatory track inspections.
The board's recommendation came out following its investigation into a fiery March 7, 2015 derailment involving a Canadian National (CN) freight train near Gogama in northeastern Ontario.
"The investigation found that certain data on deteriorating rail surface conditions are not always considered by Transport Canada when it plans its inspections," said Kathy Fox, TSB Chair, in an Aug. 3 news release.
"By integrating data on these 'leading indicators'—which could be predictive of future rail failures—the targeted inspections would be better focused."
The derailment involved a CN unit transporting 94 tank cars loaded with petroleum crude oil derailed on the Ruel Subdivision near Gogama.
Although the train was travelling below the 50 mph speed limit, 39 tank cars derailed, spilling about 2.6 million litres of product, which ignited, caused explosions, and contaminated the nearby Makami River.
A CN rail bridge was destroyed, along with about 1000 feet of track. There were no injuries.
The investigation found that the derailment occurred after a recently repaired rail within a joint broke under the train.
Three days prior to the accident, a track maintenance employee had repaired a broken rail by cutting out the defective rail and installing a plug rail.
However, a dye penetrant test to find defects that are not always visible to the eye was not performed prior to the repair, although required under CN standards.
As a result, a vertical split head, which is an internal defect, was not detected and remained in the south rail after the repair.
Additionally, following the repair, the rail head ends within the joint were mismatched.
To ease the transition between the rail heads, grinding on the plug rail head end was performed, but it was insufficient and a step between the two rail heads remained.
Given the state of the repair, a mandatory "slow order," which would have required trains to reduce speed at this location, should have been issued, was not done.
The Transportation Safety Board investigation showed that CN's procedures for rail testing and installing a plug rail were difficult to find in multiple manuals.
Employees were not given checklists, which could have outlined the steps required to complete the work.
The employee in question was aware of the dye penetrant test but had not performed it or seen it done during the course of his duties. And CN did not provide any hands-on training.
To improve future inspections, Fox noted that Canadian railways regularly inspect their track networks for specified rail defects.
"Railways gather information, including data on leading indicators, such as localized surface collapse, rail end batter, and crushed heads, and TC needs to acquire this information. Without it, the targeted TC track inspections simply won't be as effective as they otherwise could be. This is the focus of the recommendation we issued today."