The federal Transportation Safety Board is releasing later this morning its final report on the devastating train accident in Lac-Mégantic last July.
47 people were killed when a runaway train carrying crude oil exploded in the town center.
The TSB's investigation focused on several possible factors that could have led to the accident, including a possibly poor repair job that could be linked to the engine fire that night on July 6.
Other factors include the kind of oil that was being transported, the one-man crew used to run the train, how the brakes were applied, the railway infrastructure, and the train cars themselves.
Transportation safety officials had concluded in past reports that the DOT-111 tanker cars were vulnerable and likely to release their contents in an accident.
The oil was highly volatile, which was not indicated on the shipping manifest.
The railway was using a one-person crew on the ill-fated train. Transport Canada only finalized guidelines for such single-person train operations two months before the rail disaster.
The train engineer had applied seven hand brakes, when company regulations stipulated nine should be used.
That engineer, Tom Harding, and two other employees of the now-defunct Montreal, Maine and Atlantic face charges of criminal negligence causing death.