People regularly manage to fail to get off at Eridge on the 18:08 from London Bridge on the Uckfield line and find themselves getting a ride to Crowborough.
Part of the problem is that people getting off at Crowborough start getting up before the train as even got to Edenbridge (30 minutes and 4 stops from Crowborough). By the time the train gets to Erdige the door vestibules in carriage 6 are crowded with those getting of at Crowborough. Passengers wanting to get off at Eridge not unnaturally assume all these people are getting off at Eridge, by the time they realise they are not, and they need to be another carriage forward its too late, and the train is off to Crowborough.
If they are unlucky the down train is running late and the volume of people means they cant get across the bridge at Crowborough fast enough to get back!