The Transportation Safety Board says a freight train derailment near Nipigon last year was caused by the complete failure of a previously cracked rail.
The incident took place on Jan. 13, 2015, halfway between Nipigon and Schreiber.
Officials with the TSB say the 31-car Canadian Pacific train included seven tanker cars loaded with propane.
The board's investigation found that a cracked rail gave way completely as the train drove over it, causing 21 cars including the propane tankers to derail.
They add that the crack in the rail went undetected despite regular inspections because it was located behind joint bars, making it difficult to spot when the track base was covered in snow.
The TSB officials also add that CP's safety procedures were lacking in the incident.
One crew member sustained minor injuries after inhaling propane that leaked from the train.
(TBT News)
