Emily Hamer, CN Rail regional manager for public and government affairs, said that environmental factors undermined the tracks near Burnaby Lake.
"We've confirmed that the cause of the derailment yesterday in Burnaby was due to heavy rainfall that led to a beaver dam washout," she told CBC News Sunday.
"It's not something that happens a lot, but it was certainly the cause of yesterday's derailment," she said.
At around 11 a.m. seven rail cars carrying coal on a westbound CP Rail train operated by a CN Rail crew derailed near the intersection of Cariboo Road and Government Street. Four of the cars remained upright, but three were on their sides and some of the contents had spilled out into a ditch, Hamer said.
Two crew members were on board at the time, but no injuries were reported.
Burnaby RCMP Cpl. Leanne Dunlop said Saturday that it appeared that the ground had washed out.
"What it looks like is there's a portion of the rail that would have typically been on top of solid land that appears has eroded into the track area," she said.
Transportation Safety Board spokesman John Cottreau said Saturday it was too early for his agency to determine the cause of the derailment, but an investigator was at the scene.
"He's taking photographs, he's documenting the site, he's taking measurements and interviewing witnesses," Cottreau said. "He's gathering all the information that he can so a decision can be made on what type of investigation we're going to do on this occurrence."
Environmental concerns grow
Crews from several agencies and companies worked overnight to clean up the site, but environmental groups are concerned that the coal that already spilled is posing a threat to fish in the nearby waterways.
The spill happened next to Burnaby Lake, which connects the Still Creek to the Brunette River, and ultimately the Fraser River.
Nick Kvenich, who volunteers with BurnabyStreamkeepers, explained that coal dust can be hazardous to fish.
"One thing we don't want to see is you don't want to see this stuff blacken the creek because then it gets into the gills of fish, and that means they have a hard time to breathe," he said.
Kevin Washbrook, with the group Voters Taking Action on Climate Change, believes things are only going to get worse if coal transfer facility expansion continues in the region. Washbrook's group is concerned about plans to expand a coal transfer facility at the Surrey Fraser Docks, and about plans already underway to increase coal shipments out of North Vancouver, where this train was headed.
"The port authority just approved a potential tripling of coal out of Neptune Terminals," he said.