@Haywain
Given what you have mentioned ref impact of court case on work/dismissal for your daughter I think you and she need to be sure of this given the trade off concerned if it goes to court and she is found guilty - which is likely, as others mentioned. Such an outcome may result in lower cost (fine etc), plus record - possibly lower cost, even than the train company may settle out of court, but of course if the consequences are a loss of job and the income from that, then a decision to pay a specialist solicitor in the hope they can mitigate it may be considered worth the expenditure.
Discussion with Union, professional body and even HR to be clear about that will thus be important. A good HR person should be able to advise confidentially, unless they are bound to suspend you just for raising the possibility. After all this is a train fare evasion case, not admitting to them medical negligence or theft from employer or some such.
I personally think that @WesternLancer is being a bit alarmist. You mention in your first post that your daughter works in the NHS, but (quite properly) doesn't specify what type of role. I think the only requirement is to disclose any convictions to your employer - it would be much worse if you didn't - and I'm not convinced that a fare dodging conviction would result in suspension or worse. (The only exception could be if she had a history of a poor disciplinary record, negligence, poor performance etc, and this is the last straw which breaks the camel's back.) If she is in a post where there are often vacancies and which is hard to recruit to, that may be in her favour.
I used to be a manager in the NHS, and I don't think that an offence committed outside work and not impinging on professional performance would be detrimental. Would a speeding conviction lead to dismissal? - I think not. Likewise a fare dodging conviction.