There are porters at some stations who can be hired to help passengers with luggage. Porters can be hired at Roma Termini, Milano Centrale, Bologna Centrale, and Firenze SMN.
These porters will typically lift your bags onto your train, and often they'll stow them for you in the baggage storage section of your car. Unless you're traveling to a station with a similar service—and enough time to locate a porter while the train is stopped—you'll be responsible for getting your bags off the train at your destination.