Checking baggage on the train

There is no sort of system to check bags on trains, you take care of your own luggage. If your luggage is small enough, and light enough to lift, I would advise lifting it and placing it in the spots above your head (similar to carry-on spots on an airplane). If the luggage is larger, you basically have two options. You can either store it in the area at the beginning or end of the train car. (Some people choose to use a chain and lock it in there, but I don't usually worry about safety there.) The other option is on trains where the seats face each other, there will be a ^ shaped area between the seats with backs to each other. This room was large enough for me to slide my medium-large sized suitcase, standing up, into the area. Ron in Rome's blog has some excellent information on this topic, and about using the trains in general. Trains do not stop for long, and as soon as everyone has exited at their stop, people will start entering quickly. You will want to be standing at the door, with your luggage, before you arrive at your stop.

The bad news for you is no luggage check but the good news is no security check either. Some train systems have a luggage forwarding system but not the Italian trains. Another option would be to use a service like FedEx, UPS, etc. to ship your luggage ahead. Your options are limited.

B.D., I have a few comments to add to the others. If you're travelling in a second class Car with "open seating", if the car isn't too crowded you should be able to keep your luggage with you. If you're travelling in a car with compartments, place smaller / lighter bags on the racks above your seat. Again, if it's not too crowded you should be able to keep larger bags with you in the compartment. If the cars ARE crowded, you'll have to place larger bags in the luggage racks, which are usually located at the end of the cars. I'd suggest keeping watch on them, as they could "disappear". Be especially vigilant when the train is at the station. As it's been awhile since you've used trains, you may find it helpful to review the "Rail Skills" chapter in Europe Through The Back Door. You could also download the free PDF Rail Guide from the "Railpasses" section of this website. Although slightly "dated", This Tutorial from Rick may also be useful.

Chani is right, you should have no problem finding someone helpful to assist you lift the bags into the car if they are too heavy for you. It can be tough to lift them up that high and climb the steps at the same time.

B.D. is all your travel going to be in Italy? If traveling to Switzerland it is possible to check your luggage at the station and have it meet you at your hotel. I can't find that option on the SBB website, but I'm sure it existed.

Cable locks are good for the train. I have a cable (have no idea where or when I got it) with loops at both ends, to use with a lock. Lightweight, any lock works. No, I don't really think anyone is going to walk off with my suitcase, but locking it to the luggage rack gives me peace of mind during the journey. I usually find a man boarding or alighting who will lift my suitcase on or off the train quite willingly (sometimes someone does it just to keep the traffic moving :-). I have also had men volunteer to carry it up a flight of stairs in train stations when I look like I'm struggling with it. The only train station I found in Italy that didn't have either a ramp or an elevator was in the CT.