Train from Venice to Rome

Raymond, For most trains on that route, reservations are compulsory so those will be included with your ticket. There are numerous trains on that route every day, so you shouldn't have any trouble at all getting tickets unless it's a major holiday or whatever. I don't usually buy tickets in advance, as they're so easy to buy in Italy, either from the staffed ticket windows (usually long queues) or from the automated Kiosks. I'd suggest buying your tickets at least a day before you'll be travelling, as you may be able to qualify for the discounted "Mini" fares. You might find it very helpful to have a look at This Website, as it provides a lot of good information. Happy travels!