Sept 5th train strike

You don’t say what cruise port you will be disembarking at or at what time, but some local trains (“Regionale” trains) in Italy are required to run from 6am until 9am and again from 6pm until 9pm Mondays through Saturdays even during rail strikes. They can stop in transit wherever they are at 9am and 9 pm. Since the strike begins at 9pm on September 4, you’ll be fine if arriving on the morning of September 4 as long as your return journey to the port city concludes by 9pm on September 4.

Depending on the port you are docking at—presumably La Spezia or Viareggio—buses to Florence also may be an alternative.

Trenitalia publishes an online list of its high-speed “Frecce” trains that are guaranteed to run even during rail strikes. Italotreno also announces a few days ahead of a rail strike which of its trains will run.

Look at the page https://www.trenitalia.com/it/informazioni/treni-garantiti-incasodisciopero.html to see what trains will run (it's in Italian, you'll need to use a translation service such as Google Translate or thru your browser)

I don't think all regionale trains run during the guaranteed hours since that page has a clickable links by region of which trains run and on weekdays they look like they're predominantly from 6:00 to 9:00 and from 18:00 to 21:00. If all regionale trains run during those hours they wouldn't need the tables

The notice says régionale and Alto Adige, ie the Dolomites region around Bolzano. I have trains on the 4th and 5th, too. ;—)
Jean posted a link to look up strikes on another thread.

You can also phone Trenitalia and ask for an English speaker to talk to.
I did just that last year when strikes threatened my trips by train.
If you search the website closely, eventually you’ll find out how and where to call them, it’s not immediately obvious.
I’ll have a look and add it here when I find it.

Elizabeth, I’m seeing it’s a nationwide rail strike targeting both Trenitalia and Italotreno and some local transportation.

It's affecting ITALO also... and I'm desperately trying to understand if my train from Naples to Rome is just delayed or canceled.... as Italo's webpage only indicates certain trains "could be" affected. It's my train to FCO on the morning of my late afternoon flight. I haven't received anything from Italo about changing my reservation.

Unfortunately, Italo doesn’t post its list of cancelled trains until just a few days before the actual strike date. Italo doesn’t have a pre-set list of guaranteed trains that will run as Trenitalia does. Instead, Italo decides its strike schedules on a piecemeal basis.

If you have an international flight out of FCO on September 5, my advice is to book a train now that departs Naples for Rome on September 4 before 6 pm so you’re certain to make your flight. There currently are several high-speed trains on 9/4 with tix for less than €25 If your Italo train is cancelled, Italo will refund your money and you can use your new back-up ticket on 9/4. If your Italo train runs, then you’ll only be out €25 or nothing at all if you buy a refundable ticket. The cost of an unused train ticket will be much less costly than having to pay for a new airline ticket to get home should you miss your flight.

BTW, the Leonardo Express trains from Rome Termini to FCO are guaranteed to run even during rail strikes.

Found the Ministry of Transportation listing of strikes:
https://scioperi.mit.gov.it/mit2/public/scioperi

I've contacted an Italian contact to learn if the union involved is large or small, which will give an idea of how well followed the strike might be.

*

www.thelocal.it. The second headline from the top.

The nationwide strike is also now embedded in AI summaries.

If you scroll way down on the Trenitalia website, you’ll see a section “In case of strike”.
Right at the end in the contact area.
You can translate it to English.
Then you can see lists of certain trains that will run.
Hope that helps.