I reached the same conclusions as
@tspaul26 regarding the application of
Goldstein and the conjoined appeal of
Rimmington, which was also concerned with the common law crime of public nuisance, now abolished by Section 78(6) Police, Crime, Sentencing and Courts Act 2022.
The specification of charge set out in the OP's post #12 strikes me as somewhat puzzling:
“That you on ** between Maylebone and ** stations did contravene Byelaw no 17 (1) of the Railway Byelaws made under section 219 and schedule 20 of the Transport Act 2000 in accordance with the Railways Act 2005, in that you entered a train in a compulsory ticket area for the purpose of travelling on the Railway without having with you a valid ticket entitling you to travel.”
The Byelaw 17(1) offence involves entering a compulsory ticket area on the railway. That could include a train provided it had been identified as such in a relevant Penalty Fare Scheme and by display of the requisite notice. My understanding is that certain station platforms and associated areas managed by Chiltern Railways continue to be treated as CTAs, but not the trains themselves. FWIW, Marylebone wasn't included in the list of CTAs supplied
in this post, although I should be surprised to learn that it had ceased to be such. But my point remains: why specify a Byelaw 17(1) charge in terms of entering a train, when the more appropriate charge would surely be one of entering the CTA at which such train was boarded? Or is this a case where there is doubt about the station at which the train was boarded, and whether it was a CTA?