Trains
Trains in Italy are operated by Trenitalia and by a few others smaller companies that only handle local transportation.
On the Trenitalia web site you will be able to query the on-line train schedule as well as to buy tickets.
Travelers coming to the Naples/Sorrento area will also be interested in the Circumvesuviana trains. The Circumvesuviana railways connect Naples with Sorrento, Pompeii, Herculaneum and the other villages of the area. The map of the railway network is available on Circumvesuviana web site. An interactive schedule is also available (unfortunately most of the Circumvesuviana web site is in Italian only).