@Tentx, your story may be more credible if you can say something about yourself that puts the mistake in context.
Three possible benefits of hiring a solicitor:
1) They may prompt you to come up with a useful line of defence.
For example, you may have convincing arguments that you are a bit dreamy or get confused in some situations. (I'm not saying those are the case - they are examples; although if your friends thought you were very dreamy, someone might wonder why your friends would let you buy the ticket.)
2) A solicitor may help you to express more convincingly, or offer assurances, that you are telling the truth.
3) The company and/or magistrates may take the same defence more seriously just because a solicitor is involved.
The company may see time discussing the case with a solicitor as more hassle than they want, and so not prosecute. As I said above, the decision whether to hire a solicitor depends on personal factors.
Many people might not relate to your saying the wrong station name, as a mistake they would make themselves. So is there more you can say about yourself that's relevant, bearing in mind the general comment you made earlier? You don't necessarily have to convince the company you're innocent; they may settle (it might be optimistic to think they'd drop this case) because they think you would sow enough "reasonable doubt" in the minds of magistrates.