I'm not sure that you made an error. If you check the timetables at , it shows that about half the trains between Rome and Florence are Eurostars. (There's some confusion because the trains that go through the English Channel Tunnel are also called Eurostar.) These trains make the Rome-Florence trip in around 1.5 hours, require reservations, and cost the most. Others are InterCity (or EuroCity if they go internationally); they take 2.5 hours, generally don't require reservations, and have a smaller supplement. Then there are diretti, which just cost the base fare and take around 3.5 hours.

Andrew Missouri