Italian authorities say a speeding out-of-service train has slammed into a group of workers doing nighttime track maintenance, killing five of them. The crash occurred shortly after midnight at a station in Italy's northern Piedmont region. Piedmont's governor says the cause of the accident is under investigation. The town mayor says early information indicates that the crew of the train was unaware that there were workers on the tracks. Authorities estimated the train's speed at about 60 miles per hour. The train consisted of an engine car which was transporting 11 empty passenger cars. Two workers who avoided being hit were being treated for shock.