Welcome to the forum!
@Fawkes Cat has mentioned the advice I've given to other posters in a similar position to yours so I've posted it here for ease.
You are likely to receive a letter from the train company (or an investigation company acting on their behalf) which will probably take a few weeks to arrive saying that they have received a report, are considering prosecuting you and asking for your version of events. It is important that you engage with and reply to this letter. You might want to include the following in your reply:
- That you are sorry for what has happened
- What you have learned from the incident
- That you are keen to settle the matter without the need for court action
- Offer to pay the outstanding fare and the train company's administrative costs in dealing with the matter
Make sure your reply is short and concise, don't give a sob story - they've heard it all before. Most train companies are usually prepared to offer an administrative settlement (commonly known as an out of court settlement) for people who engage with the process and who haven't come to their attention before. There is no guarantee of this and the train company would be well within their rights to prosecute you in the magistrates court.
If you are offered a settlement the amount varies depending on the train company and circumstances but tend to be a few hundred pounds plus the outstanding fare. An out of court settlement might appear to be a fine, but it isn't and you won't have a criminal record as a result of accepting one.
Feel free to post a copy of the letter when it arrives (with personal details removed) and I'm sure members on here will be happy to assist in proof reading your reply.