The Otter Tail Sheriff's Department says the 94-car train was headed south Wednesday morning near Parkers Prairie when it lost air pressure and went into an emergency braking mode. Fourteen cars derailed.
Spokesman Dan Olson of the Minnesota Pollution Control Agency says more than 20,000 gallons of crude oil, or about 76,000 litres, has spilled or leaked.
Olson says one heavily damaged car has spilled much of its 26,000-gallon load and two others tipped over and are leaking.
Olson says there is no threat to ground or surface water because the ground in the area is frozen.
CP Rail spokesman Ed Greenberg says the railways is cleaning up the spill.