Apr 29, 2013 - 02:17 PM
I think the answer depends on what type of train you have e-tickets for. I believe the e-tickets for the Freccia trains (-rossa, -argenta, -bianca) specify a car and seat number (your reservation), but the local lines often do not have reserved seating, so you show up at the station, get on the train, in a car that matches your class, and show the conductor your e-ticket/PNR sheet. Most of the time, on the local trains, there are more than enough seats open. Some local trains may only have 2nd class cars, so even if you think you bought 1st class, your only choice is a seat in a 2nd class car--and they're usually comfortable.
We just made a day trip from Bologna to Ravenna and back again, on a local train. It had plenty of seating (basically empty) in 1st class, but the return train only had 2nd class, but still had plenty of comfortable seats available.