Investigators have ruled out extreme heat and conductor error in a Monroe County train derailment, the second in central Indiana in less than a week.Indiana Railroad officials said the train, hauling Indiana coal, jumped the tracks seven miles west of Bloomington, turning about 28 train cars into a twisted metal mess and spilling tons of coal on the ground.At first, investigators thought the extreme heat may have caused a phenomenon known as sun kinks, which cause the steel tracks to expand and contract."The engineer was acting properly. Everything was going well there," said Eric Powell with Indiana Railroad. "There are no signs at all of sun kinks. The engineer didn't report any problems. We haven't seen anything with our investigators so far."By law, the company is required to routinely inspect lines to keep trains on the tracks. During hot weather, Powell said there are more inspections to check for trouble spots."Safety is almost a religion. It has to be because we're working around equipment -- 200-ton locomotives, 10,000-ton freight trains. They operate 24 hours a day, seven days a week in all kinds of weather," he said.Neighbors near the derailment said they never gave much thought to the possibility of cars jumping the track."It wouldn't even be just our house. It could take out everybody on this cul-de-sac. All that power, all that steel and everything," said Shannon Nelson.Officials said they expect it to take several days to clean up the mess outside of Bloomington. A safety expert will help determine what caused the derailment."It's a company that's kind of like the 'CSI' of rail investigating," Powell said. "They get in there with a lot of scientific data to find out what's going on."Another train jumped the tracks in Morristown on Wednesday, plunging several cars into the Blue River.