A derailment has blocked Canadian National Railway Co's main line in northern Ontario, the railway said in a service bulletin. In a separate statement CN said early indications were that most of the cars that may be involved were residue cars, tank cars that recently carried flammable liquids. There were no injuries, and no indication of any fire. CN said traffic running both directions along the route, which links Toronto and Winnipeg, Manitoba, could be delayed by 24 hours or more. Several crews, including CN's dangerous goods department, are responding to the area, near Minnipuka, Ontario. (Reuters)