What is rail security like in Italy and France

It is hard to redirect a train and difficult to get to the driver so little concern about knives and liquid. The Spain AVE has a little prescreening walk through but they are worried about bombs. Same for the Eurostar between Paris/Brussels and London. Your knife is fine.

Never without my Swiss Army Knife! Put in my checked luggage for flying, of course, but never had a problem on European trains.

Mel, you should have no problem with a Swiss Army Knife. Except for the trains mentioned in previous replies, there are no "airport style" security checks on most trains in Italy and France. ¶ However, especially in Italy be sure to keep a close watch on your luggage. I've seen a few cases of "disappearing luggage" on trains.

I opt for a good sturdy plastic knife/church key now.It just is not worth losing your swiss knife altho I have never expereienced scanning or sim for train or bus rides in those countries.

No problems with trains. I'd say your biggest issue may be with museums - most have security now and some may confiscate knives that they deem pose a risk to the artwork. The only one I know for sure that will confiscate is St. Chapelle in Paris but that is because it's in a government compound. A few churches in Italy also screen - like the Vatican and Milan's cathedral - but again I'm not sure if they are concerned with knives or not. Best to leave it at the hotel.

Thank you all for the info.

Italy has none, zero, zip! Buy your ticket and walk to your train and board it, bags in hand.