Just a remider to folk that you need to validate your train ticket before you board the train.
We bought tickets at Stazione Centrale di S. Maria Novella in Florence for a trip to Pisa.
We did not realise we had to validate the tickets on the platform before we got on the train. We could have incurred a fine, only that the ticket inspector let us off!
Stazione Centrale di S. Maria Novella