Please check out the entries already made on this topic. In brief, we took the train from Termini to Civitavecchia last May. It was hot. 85 degrees. Hassle at the Civitavecchia with luggage because there are no elevators. No matter what anyone else says, it is a long walk to the ship from the train station. Cost of cab was $20 euros. Worth it. With a three year old, would be a double hassle to walk to the pier. The train is doable but even with an ll year old - we still had to watch our bags, his bags, there were lot of teenagers on the train and there are lots of little thieves so when travelling with a child - you are at a disadvantage on the train. The thieves will have their eyes on you. Watch your valuables because they know you got to watch your child. My opinion start you holiday on the right foot and take the ship transfer. I would not get to that pier via train on our own again. Trip is easy with no luggage. But luggage and a three year old, you are just asking for hassles. Have a wonderful trip once you get on the ship.