Derailed CN rail cars are seen near Gainford Alta., in an undated handout photo provided by the Transportation Safety Board of Canada.HANDOUT/The Canadian Press
Officials monitoring a train derailment near Edmonton are planning another controlled burn to get rid of any remaining propane in the tank cars that left the track over the weekend.
It's the second time in as many days that CN Rail has attempted to vent and then ignite the gas that remains on the train.
The first controlled burn took place Sunday night, but it didn't get rid of all of the gas.
The procedure involves placing small explosives on the hulls of the derailed propane tank cars, then detonating them to punch small holes in the pressurized car shells.
The gas vapour ignites as it escapes and is supposed to burn off in a controlled manner.
People in the hamlet of Gainford have been out of their homes since early Saturday morning when 13 cars on a freight train went off the rails about 80 kilometres west of Edmonton.
As of Sunday, 126 people had registered with the evacuation centre.