The incident at Drumhoney Holiday Park in Irvinestown happened on Sunday at about 11.30am.There were no serious injuries and all those taken to the South West Acute Hospital in nearby Enniskillen have now been released.The train was on one of its regular trips around the park when the central carriage turned over.Park owner Ivan Bradshaw said it was not clear what had caused the accident.He said the train trips round the site were organised to raise money for charity."We just don't know what happened at this stage, it's under investigation," he said.The Health and Safety Executive NI said it was liaising with the police and Fermanagh District Council over the incident.A hospital spokeswoman said: "Five adults and 12 children were treated for minor injuries. All of them have been treated and discharged."On Saturday, a woman and four young children had to be treated in hospital for minor injuries after the miniature train they were in overturned near Newtownards, Co Down.They were treated and discharged within hours for what an Ulster Hospital spokesperson said were "non-serious injuries."They were hurt when a miniature train, run by the Belfast and Co Down Miniature Railway Society toppled over on its track, at the Drumawhey Junction, located at the Four Road Ends/Upper Gransha Road, just outside Newtownards.