[Jack_]

As is often the case with fights, when two people begin having a slanging match which includes the use of bad language and verbal abuse to each other and then one of them eventually flips out and initiates the actual physical fight with the other person, who would and should be charged with physically abusive behaviour? The person who initiated the actual physical part of the fight of course, I don't see how that could be disputed.

You can argue all you want with verbal insults (which of course is still a criminal offence), but that does not give you the right to take matters further and then escalate it into a physical fight. And it is basically the same principle here really - just because the guy was being verbally abusive, it does not give anyone other than relevant authorities the power to then use physical force to remove him from the train when he posed no physical threat to anybody.