Teamsters Canada Rail Conference

FORT SASKATCHEWAN, Alta. - Canada's major railways are investigating after two of their trains derailed in Alberta and Saskatchewan on Tuesday.

Canadian National Railway (TSX:CNR) is investigating what caused 15 cars to derail at a rail yard near a petroleum refinery north of Edmonton.

Canadian Pacific Railway (TSX:CP) is also trying to figure out why four cars went off the tracks near Rose Valley, Sask., spilling canola and canola oil.

There were no injuries in either incident.

In Edmonton, 13 empty cars left the tracks at the CN Rail yard near Shell Canada's (TSX:SHC) Scotford refinery and tipped onto their sides.

Two other cars stayed upright on the tracks and did not leak any material during the incident.

Kellie Svenson, a spokeswoman for the rail company, says the cars were moving at slow speeds and derailed while they were being switched around in the rail yard.

She says they're still trying to determine how the incident occurred.

The refinery, about 40 kilometres north of Edmonton, can produce about 100,000 barrels of synthetic crude oil each day and also produces such things as gasoline, jet fuel, propane and diesel.