Most trains however have a space [0] at the end of each car where you enter and exit. That space can also have a toilet, bike storage, various (locked) train controls, sometimes even a few seats [1] where you can sit if your call will be a while.
0: https://www.cornwallrailwaysociety.org.uk/uploads/7/6/8/3/76...
1: https://www.modernrailways.com/sites/modernrailways/files/im...
No one beside myself has ever told him to stop because I think being old gives one a bit of a 'get out of jail free card ' with regard to social behaviors.
I would love for you or someone like you to happen upon him and tell him to knock it off, but alas that seems fleetingly rare.