We booked train tickets for travel earlier this year on the above linked Ferrovia (Trenitalia) website. There was a suggestion that some foreign credit cards won't work, and IIRC, I did have a problem with one CC, but the next one I tried worked. Printed out barcoded ticket/seat allocation- all very easy, even changed one of the reservations we made over the net (to a train one hour later) using the booking reference and one of the ticketing machines at the station - no problems.