I was travelling to Canterbury some time in the 1990s and there was a "kerfuffle" on the train, which I later found out to be a group of boys "steaming" through the train (basically robbing people and running away). The train stopped just short of the station, and the driver said that "there was a signalling issue" and we would be on our way shortly. About 5 minutes later, 2 police cars turned up, and the police walked up the track to the train and were let on by the driver and when we pulled into Canterbury, we saw 2 young gentlemen in some form of restraint being helped from the train, no doubt to assist Her Majesty's Kent Constabulary with their enquiries.