PARKERS PRAIRIE, Minn. -- Canadian Pacific Railway Ltd. has lowered its estimate of how much crude oil recently spilled during a derailment in western Minnesota.

The Minnesota Pollution Control Agency says the railroad now estimates less than 56,700 litres spilled Wednesday. Initial estimates were 75,700 to 113,500 litres.

The MPCA also says the freezing temperatures that helped contain the spill have made it difficult to take up the spilled oil.

Only about 3,800 litres had been recovered as of around midday Thursday.

The rest of the oil on the ground has thickened into a heavy tar-like consistency. Collecting it is expected to take another day or two.

Calgary-based CP Rail says the clean-up has been "progressing well with no issues."

"For our railway, it is important for on-site personnel to take the necessary time to ensure the clean-up is conducted appropriately and safely," spokesman Ed Greenberg said in an email.

"Clean-up efforts are progressing well."

Greenberg says that the rail line was reopened early Thursday, following full track repairs and an inspection.

The 94-car CP Rail train was headed south near Parkers Prairie when 14 cars derailed. Three cars either leaked or spilled oil. No one was hurt.