For transparency: I have drunk on a train going to match and sung the odd song after a good win. I might even have banged on the window in time with the song. Perhaps I should be birched. bets ban me from the train.
I don't think it is acceptable to bang on the window of a train in time to a song.
Whilst you may not see anything wrong with this, you should understand that it can be intimidating and threatening to other people on the train.
Section 6.2 of the railway byelaws, which you agree to abide by when buying a ticket, state:-
I think it is a bit of a stretch to claim that banging on the window of a train does not constitute disorderly conduct.
- No person shall behave in a disorderly, indecent or offensive manner on the railway