Packing light, if at all possible, is our best advice. I couldn't find anything regarding luggage handling, except the following:

Services for the disabled - http://tinyurl.com/ag9s4

In all major Italian train stations, you'll find an office dedicated to facilitating train travel for disabled people. Upon request (at least 24 hours in advance for Italian trains, three working days in advance for international trains) these centres can organize transportation for disabled people around the train stations of departure and arrival. Other services include wheelchair access, luggage transport, and train information. The Termini* office is located by platform 1; the telephone number is 06 4881726.

*Termini is the main Rome train station.

Hope that helps, Linda Toronto