Here's a cellphone video from when the train was parked (and on fire) about 7 miles away from the town. And then at some point after this, the train started rolling downhill towards the town.
http://tvanouvelles.ca/video/en-vedette/les-dernieres-nouvelles/8805187001/explosions-a-lac-megantic-un-wagon-en-feu-apercu-a-nantes-quelques-heures-plus-tot-la-video-dun-temoin/2530642216001
http://tvanouvelles.ca/video/en-vedette/les-dernieres-nouvelles/8805187001/explosions-a-lac-megantic-un-wagon-en-feu-apercu-a-nantes-quelques-heures-plus-tot-la-video-dun-temoin/2530642216001