By Julie Gordon and Richard Valdmanis
LAC-MEGANTIC, Quebec (Reuters) - The only warning Lac-Megantic residents had of the coming disaster was the louder-than-usual rumble of a train - a runaway locomotive laden with crude oil that would jump the tracks, explode and burn down the center of town.
"I heard a rattle, louder than usual, so I went out on the balcony and I saw the train going at extremely high speed," said Ghislain Bisson, 52, who was watching late-night television as the train approached. "Then, I saw it. It just left the track and headed right for the building.
"The explosion occurred. I woke up my girlfriend and said, 'we have to leave, we're going to die here.'"
Much is still unknown about the cause of the disaster that struck this small Quebec town, perched on the edge of a blue lake ringed by forests of pine and birch and close to the border with the U.S. state of Maine.
The company that owns the train said the brakes somehow became disengaged as it was parked at a siding on a hill. There was no driver aboard when the train barreled into Lac-Megantic shortly after 1 a.m. (0500 GMT) on Saturday.
The death toll, currently five, could rise to nearly 50 if people reported missing are not found. That would make it Canada's deadliest accident since a 1956 plane crash in Chilliwack, British Columbia, that killed 64 people.
"My girlfriend has cousins that we're pretty sure are dead right now, 99 percent. It just hasn't been confirmed," Bisson said. "I hope to God that not a single other train like this passes through our town."
The tragedy is particularly devastating for a town with only 6,000 residents. The blast razed dozens of buildings, including a popular bar called Musi-Cafe, where many of those reported missing are believed to have been.
Bernard Theberge, 44, was on Musi-Cafe's patio when he saw the train approach. He said there may have been 50 people inside the bar.
"There was a big explosion, the heat reached the cafe and then a big wall of fire enveloped the road," said Theberge, who escaped with second-degree burns to his arm. "There were people inside. I thought for maybe 2 seconds that I should go in, but the heat was too strong to get to the door."
"It's hard, it's huge. Imagine half the town on fire," he said.
The downtown core remained cordoned off on Sunday as police, regulators and the company that owned the train - Montreal, Maine & Atlantic Railway - tried to figure out what happened. About 2,000 people were evacuated.
"I was sleeping when it happened. There was a boom and the inside of my house turned red with the color of the flames. I left with nothing but the shirt on my back," said Rene Bolduc, who lives a few hundred meters from the site of the accident. He said he saw people running as flames towered overhead.
"It felt like the hairs on my arms and face were burning off." Bolduc was not hurt, and has not been back to his house, which is in the blocked off area.
Most shops were closed and homes deserted on Sunday. Scores of men, women and children sat inside the local school, a large brick building transformed into a makeshift shelter. Children played ball in a corner room while adults napped on cots. Trucks delivered water and food.
"At least we are not out on the street," said Valerie Dinelle, 27, who sat on a cot next to her caged cat, Pixel. She said she was evacuated on Saturday afternoon when the wind shifted and blew toxic smoke into her neighborhood.
Outside, sitting in the shade, Louise Boulet, 65, looked at a local newspaper that had published an aerial view of the explosion scene.
"That is where my sister lived," she said pointing to an image of a flattened building. "She is dead for sure. If she were alive, her car would not still be there," she said, pointing to a burnt vehicle next to the building.
Her sister, Marie-France Boulet, 63, ran a women's clothing shop from the front of the building where she lived.
"She was my best friend. She died with all of my secrets, and I will guard all of hers," she said, tears welling up in her eyes.
(Writing by Janet Guttsman; Editing by Tiffany Wu and Stacey Joyce)