Actually my most recent (and in some ways most bizarre) experience of anti-social behaviour on a train came on a late Saturday night Turbo from Paddington to Oxford.
At Reading, an elderly, silver-haired gentleman (shall we say), in his 60s, or, I think more likely, his 70s, was being held up by two station workers in hi-vis vests, with a member of the BTP standing guard. He was dressed in a suit, with a tie (my guess was he'd been to a military reunion, perhaps), and he had a walking stick. The two men in hi-vis vests helped him onto the train - it was somewhat evident that he was very much the worse for drink.
On the train....ha. First, he wandered up and down between carriages, and then sat down, repeatedly abusing (in the coarsest possible terms - real Derek and Clive stuff - and in similar terms to that used on the video on the c2c above) pretty much everyone around him, before walking up and down the carriage to do the same. And waving his stick around.
No-one responded to his accusatory abuse (we were being labelled by him in no uncertain terms),and I didn't stick around to see what happened when he got off at Oxford.