Be prepared for chaos, late trains, and cancelled trains. Our Eurostar from Venice to Rome just never showed up. There was no notice of cancellation or anything. We went to customer service and the lady said we were supposed to have taken some alternate route to Padova that just left. We never heard any announcement (that we could decipher). So we went to the ticket/reservation desk, and the guy there tried to sell us 2 new tickets on the next train to Rome for 100 euro, as if we missed the train and it was our fault. It was as if he had no idea how to put us on a different train, we had a perfectly valid ticket but for a train that was cancelled. We went back to customer service, and a different lady there said "no problem!", stamped our paper ticket and told us to get on the next train and ask the conductor to assign us a seat. Happily, we went on the next train, which was now double booked. No one seemed to care even though many people had to stand for a long time.