The brakes were disabled before train exploded in Lac-Megantic, Canada according to railway chief.
A total of 72 tanker cars carrying crude oil jumped the track, setting off a huge fireball.
At least 40 people are missing. Officials in the town 130 miles east of Montreal say some victims were likely vaporized by the intense blaze, which burned for 36 hours after the crash.
The driver-less train barreled into a small Quebec town and derailed, causing a deadly inferno and claiming 13 lives.