Train Passes
Trenitalia offers various discount passes, including the Carta Verde for youth and Carta d'Argento for seniors, but these are mainly useful for residents or long-term visitors, as they only pay for themselves with regular use over an extended period.
More interesting for short-term visitors are Eurail and InterRail passes.
Read more: http://www.lonelyplanet.com/italy/transport/getting-around/train#ixzz3u077c4Gr