This seems a common occurance yet i guess resources stop them from doing much about it
It is.
The railway companies know this, of course.
But for an individual it's usually a unique occurrence and it's worrying.
So it's always worth remembering that it's common, that it's down to the prosecution to prove who committed the offence rather than the accused proving he/she wasn't the person, and the person who caused this is the person who impersonated someone by giving the wrong name and address.
It's happened to me, once, on Manchester Metrolink. In my case I guessed that it was a former tenant of mine who had given my name at the address he used to rent from me, I engaged with Metrolink in writing and the issue was dropped.
Don't engage by phone, but make sure to put everything in writing, either by letter or email.
And remember, if accused in this way, that you're not the guilty party, both you and the railway company are the victims, so engage and don't panic and - eventually - it will be resolved.
It happens all the time, and - despite the tone of the initial contact from the railway company - they know it.