'Reasonable' is a term that is used quite widely in the law, and it's deliberately vague. IANAL, and in particular I'm not a criminal law lawyer, but my understanding is that 'reasonable' is a useful shorthand for 'what, taking all factors into consideration, an ordinary member of the general public with an intention of abiding by the law would consider to be allowable'. You can see why legal draftsmen choose to use a shorter phrase when they write the law.
So you're not going to find anything written down that says that in all cases pushing someone is acceptable, but in no cases is picking them up and carrying them allowed. Rather, you have to look at the specific circumstances of each case. The level of reasonable force allowed to remove the proverbial little old lady would, it seems to me, be less than that allowed to remove a six foot tall, twenty stone, drunken and angry karate champion.
It also seems to me, in the context of 24.2(ii), that there is a minimum amount of force that the railway's authorised persons would be allowed to use - and that's the amount of force that will actually lead to a successful removal. If it came to court, I don't think that an advocate would be too stretched to argue that the purpose of the force was to remove someone from the railway - and if that aim had not been achieved then clearly it would have been reasonable to use more force.
So what are the practical implications of this, especially (as transmanche points out above) as railway staff rules probably prevent staff from using force in this way? In the immediate event of someone being forcibly removed from the railway, there's probably no mileage in that person appealing to the police: assuming the force that was used was reasonable, then the police will not criticise railway workers for abiding by their byelaws - and the police will not be interested in whether the railway workers have broken their employer's internal rules.
In the longer term, should someone feel that they had been removed from the station with unreasonable force, I don't see that the byelaws give any remedy in law: the railway workers may have acted in a way that is beyond what they are allowed to do in law, but as far as I know the byelaws don't make that an offence. The removed party could, I suppose, try to get the railway workers prosecuted for assault, which would involve the court considering whether the assault was such that byelaw 24.2(ii) gave the workers immunity from prosecution or not. I'd be interested to see that, but I suspect that I never will in that (unless you happen to be a lawyer yourself) it's the sort of challenge that would really need a good advocate to present, and good advocates don't come cheap.
If this is a hypothetical question, then the answer is that if you're being a nuisance railway staff have the power to throw you out of the station - by force if necessary - and there's nothing you can do about it. If it's a real question, then was anything other than your dignity hurt? If not, then suck it up, and try not to annoy railway staff so much again. If you really were physically hurt, then you may have a case - but be prepared for a long, expensive fight in court to prove your point, with a high chance that you will be unsuccessful.