Guaranteed Trains on a Strike Day

I am not an expert. I looked at the Ministry of Infrastructure and Transport official strike schedule page and saw exactly what you said. My understanding is that you are correct that, at least as of today, the railway sector is only planning to strike from 11:00-14:00, but I believe that could change to extend the strike hours or to cancel the strike. However, if your trains are on the guaranteed list you should be good regardless.

Hi, Giangilberto from Milan, regarding guaranteed trains: yes, that is the correct interpretation.
If they are listed in "Table A," they run even on strike days, this is the permanent list of minimum services mandated by Law 146/90. It isn't a matter of luck, it is a legal requirement.
"Up to 24 hours" is the maximum authorized duration for the strike call. It is the upper limit, not the actual duration.
"Railway sector: 3 hours, from 11:00 AM to 2:00 PM" is what the railway workers actually announced. Meanwhile, the maritime sector announced unspecified arrangements for the same strike.
So, for trains, it is a three-hour window, meaning your scheduled times fall outside it.
Changing the arrangements requires a new strike announcement, and with that, ten days' notice,that is what the law says.
Today is September 13th, and the trip is on October 2nd, so a change is still technically possible, but if it happened you would know at least ten days beforehand, you would not wake up on 2 October to a surprise.
The strike can be called off, and this often happens at the last minute. The place to check for this is the Ministry of Infrastructure and Transport (MIT) registry, the link below:

https://scioperi.mit.gov.it/mit2/public/scioperi

You can check the register up to the day before, and if the strike disappears from it, that means it has been called off.
Even if the train is guaranteed, the station can be chaotic, due to reduced staff and cascading delays.
Arriving with plenty of time to spare remains a sensible idea.

the railway sector is only planning to strike from 11:00-14:00

Not the railway sector, but the CSLE union is calling on its members in the railway sector to go on strike.
However, the CSLE is a small union, and although it is calling for a national strike, its influence is limited. It is primarily active in southern Italy (Campania and Sicily).

There will likely be no impact on your train trip, especially if it is included in the list of guaranteed connections.

Thank you so much for the reassurance. I wasn't very concerned about it but then saw someone mention the strikes that day and they made it seem like no trains in all of Italy would run for 24 hours. It made me second guess myself. I didn't want to go into it ignorantly thinking there would be little impact for us.

We will ensure we are there in plenty of time but also plan that there could be delays even though our trains are at 6:00 and 18:00 that day.

Thanks again!