Nov 11 (Reuters) - Canadian Pacific on Wednesday said a broken rail caused a weekend freight train derailment in Wisconsin that resulted in an oil spill and a precautionary evacuation.
No one was injured in the incident on Sunday, which caused an oil spill in Watertown, about 50 miles (80 kms) west of Milwaukee. Workers stopped the leak, which the company described as minor.
The track defect was not visible to the naked eye, according to CP spokesman Jeremy Berry, in a statement.
Berry said that CP's track inspection process involves the use of rail flaw "detector cars" that use ultrasonic technology to detect problems the eye cannot see. The technology last passed over the site in late September and nothing was found, Berry said.
CP also does visual inspections of the track three times per week, Berry said.
Canadian Pacific said 35 homes were evacuated on Sunday as a precaution. Everyone has since returned to their homes.
It was the second freight train mishap in Wisconsin in as many days. The other incident involved 25 cars from a BNSF Railway Co train hauling a variety of freight, including tankers of ethanol, in a rural community close to the Minnesota border on Saturday.
Thousands of gallons of the denatured alcohol leaked into the Mississippi River as a result of the Saturday accident. (Reporting by Mary Wisniewski in Chicago; Editing by Ken Wills)