But I have to admit that I wondered about the size of the fine - perhaps there was more to the incident than was reported by the Chronicle?
Merseyrail are very zealous when it comes to feet on seats and taking action for it. Usually in the form of a fixed penalty of, I believe, £60. Failure to pay, or desire to be heard in court can lead to a trip to the Magistrates. It can also be straight to court if you have previously been given a fixed penalty for the same offence.
As for the size of the fine in this partucular case, it's likely related to income.