Train ques first timer

The websites of the two companies where you can book trains are:
www.trenitalia.com (Freccia trains)
www.italotreno.it (Italo trains)

However the website below, reports trains from both companies and you can book here also at no extra charge:
https://www.thetrainline.com/

Book using any of the above websites.

The level of service of the two companies is similar, therefore choose the one with more convenient time (or better prices) for your day of travel. Italo has often better deals, but Trenitalia has a more extensive and frequent network.

The Europe rail site is a third party agency, so you will likely pay more for the commission.

Be careful about regional train tickets - the ones with no reserved seats. If you buy PAPER tickets at the station, from an agent or from a machine, those MUST be validated in the yellow box BEFORE you get on the train!!! Otherwise, you risk a steep fine if an inspector catches you without a valid ticket. There are no "warnings" for clueless tourists. (And you can't buy tickets on the train.)

If you have a reserved seat on a specific train - or you have booked an electronic ticket on your phone for a specific regional train - then no need to validate those. You can just show the QR code of the ticket on your device to the conductor.

The Trenit app is handy for purchasing tickets (for Trenitalia or Italo) on your phone as well. And you can use it to find train delay information and platform information if changing trains - handy to know before you get off the first train which platform the second train will be boarding from, or if it is a tight connection and the second train is late, you can relax a little.

A great resource for learning all about Italian trains:

https://www.seat61.com/Italy-trains.htm

I wouldn't book through the website, though, nor through Rail Europe: use the sites Roberto has provided.

Thanks so much, I will look at both.

Also www.loco2.com. Thetrainline has started adding a 2-3% fee, at least for USA residents.

I’m going to book on Italo trying to determine if it’s doable to catch a 9:25am train Naples to Rome leaving Positano that morning with private car transfer. I’m guessing it’s a 1 1/2 drive to Naples?

Instead of guessing what time you'll need to leave Positano, you can tell the transfer company you need to be at Naples Central station in time to catch a 9:25 train and they'll tell you what time they need to pick you up. If you plan to purchase tickets at the station, mention that so they can allow some extra time.

md,

I sent you a PM with information on the trains and other public transit in Italy. Hopefully that will answer most of your questions.