Online ticket booking and travelling on different train
 

If I book a ticket online for a particular train but then have to travel on a different one, is the ticket still valid?

And if the earlier one is a special web fare but the later one isn't, can I just pay the difference to the ticket checker onboard?

Don't want to go booking the ticket online then if i travel late end up having to either queue for the ticket desk anyway, or get fined for not having a correct ticket.

If the ticket is a special web fare ticket you must travel on the train as booked. If you don't you will have to pay the difference between the web fare and the normal web price, probably through a intercity extension ticket obtained at the booking office before travel

If the ticket is a standard fare ticket, e.g. non discounted standard price return student, weekender, faircard etc it may be used on other trains on the same day provided they are not booked out.

To be fair Irish Rail are quite flexible, but for every price reduction you lose flexibility its a trade off that must be accepted to get a cheap deal.

Thanks Mark, I'll just go with the standard return so.