we bought a 1st class flexi train pass--after it is registered day 1--can we just walk on trains or do you always have to go to ticket window to sign in 2-are reservations needed Naples to Venice in April-on a high speed train
Don't just walk on train unless you want a big fine. If a train REQUIRES a seat reservation then must purchase that reservation in advance. A regional/local train does not permit reservation so you can just walk on those trains. Everything requires a fee and it varies by train and varies by class of train with the high speed being the most expensive. I am curious -- what did you pay for the pass?
Read the info with the pass, but generally with flexipass, you must first validate it at a ticket window. Then each day you use it, you fill in the current date. For trains, check the schedule, if an "R" is indicated, then reservations are needed in addition to your pass. The fastest trains always require reservations, 10 euro in Italy (Including the Naples-Venice Train) Many Intercity Trains (IC) require reservations now as well, maybe 3 euro, or they may be optional. Regional and slower trains have no reservations, and as long as you have filled the date in on your pass, you can jump on and off at will. Reservations can be made right up to the time of travel.
I agree with Frank. Your pass will get you a free ride on the Regionale train only. This is the local train that makes every stop just like a bus does. The next level up is the Inter-City (IC train). You will need to pay a 3E supplemental fee (including seat reservation) before you jump on the train. For the nicer Eurostars, the supplemental fee will be 10E. Hopefully, you will get a chance to find out that 1st class only gets you a bit more leg and arm room. Nothing more. 2nd class is just great on the trains in Europe.
As Frank and the others mentioned, it's VERY important to have a valid reservation for trains which require them, which includes EuroStar Italia / Alta Velocita high speed trains from Naples to Venice. Without the reservation, you WILL be fined and it WON'T be cheap! The reservation will be specific to a particular train, so if you take a different train the reservation won't be valid. Be sure to read through the information provided with your Railpass. You may also want to download the free PDF Rail Guide from this website. Click the "Railpasses" tab at the top and then look in the lower right corner for the link. Happy travels!