Need help navigating Train Strike in Italy

I think you need to find out whether the Tirano to Milan part of your trip is also affected by the strike. That line is operated by Trenord. A Trenord webpage says some of their trains may be affected on July 8 but that the guaranteed morning trains before 9 am will run.
My thought is that if you can get to Milan as planned and then get a direct bus to Venice, that should be ok but if getting from Tirano requires too many bus changes you might want to change your plans to travel on July 9th instead. That would be my preference if at all possible.

Renting a car might be an alternative. Italo is also listed as part of the July 7-8 strikes, so that is not an alternative. I don't know anything about how refunds work with tickets purchased via Trainline. If you are already in Italy and near a staffed train station, you might be able to get help and information there.

There are trains - especially long distance fast trains - that are guaranteed to run during the strike.

Here is the English language page about guaranteed trains: https://www.trenitalia.com/en/information/in-case-of-strike.html that leads you to an Italian only page with more detail. Certain long distance trains are guaranteed to run - usually in the morning and late evening.

Here is a list of long distance trains that are guaranteed to run in case of strike: https://www.trenitalia.com/content/dam/trenitalia/allegati/info/treni-garantiti/Treni-garantiti-giu25_dic25_TAB-A.pdf

According to this it looks like there are some options:
9426 NAPOLI CENTRALE 14:10 VENEZIA SANT A LUCIA 19:34
9428 NAPOLI CENTRAL E 15:09 VENEZIA SANT A LUCIA 20:34

I know it's asking a lot but have you considered getting to Milan a day early if you can? If you can get a ticket on one of the guaranteed early trains it might be worth it if your schedule allows. As the day goes on the issues and complications stack up. Once just getting from Bologna to Verona (:30) after a flight on the evening of strike day I saw trains reporting 2+ and 3+ hours late on the station board.

I was trying to get only from Verona to Venice during a national strike so I bought a ticket on the last guaranteed morning train from Verona to Venice as well as a .Italo ticket for 20 minutes later. The Venice train showed up late, stood in the station for about 20 minutes and then slowly rolled onto Venice. I assume because it was the last guaranteed train they were making a point by running it late and very slow. I have no idea if the .Italo train went or not because I was waiting the the station on the train before it finally went to Venice.

Also for what it's worth when I went to Venice during a National strike the vaporetti were running at an absolute minimal schedule and were essentially useless because so many people were lined up to use the one an hour that was running. You might want to have a plan for Venice as well once you arrive. The Alilaguna was running that day despite the strike so I bought a ticket and took that. The dock near the train station is around corner behind the KFC.

Good luck,
=Tod

There are only buses from Tirano to Lecco due to train track maintenance on the line until at least September 15, 2025.

Those buses should run from 6am-9am and again from 6 pm to 9pm even during the time of the strike.
You should expect all transit—except for the limited list of guaranteed Trenitalia and Italotrains— to stop running between 9am and 6pm during the day of the strike.

So, traveling on Itabus. Flixbus or another bus company from Milan to Venice is the back-up plan if you cannot move up your travel day from Tirano to Venice to one day earlier.

www.Itabus.it

Thankyou very much everyone for your thoughtful replies. Huge help.

At the moment, we do have an overnight accommodation at Tirano (after a late finish Bernina Express). The booked train tickets from Tirano and Lecco is at 9:35am so it probably won't run. Tried to change that booked ticket to an earlier time but it still does not help as i would need a connected train from Lecco to Monza after 9am which would not be likely to run due to the strike.

So now we are thinking of staying two nights at Tirano and travel to Venice on 9th (not ideal as we would only have one night in Venice) before getting back on the train to Rome. Any suggestions as to what we could do in Tirano for 2 nights? We have two kids aged 14 and 16. We thought maybe we could somehow take ourselves to Lecco for 8th? But not sure. First time in Italy here, travelling all the way from Australia.

One possibility would be to get off the Bernina train at one of the scenic Swiss stops with hotels and hiking before Tirano and spend the night of the 7th there and much of the 8th there. Then, continue to Tirano for the night of the 8th. If you are taking the Bernina "regular" train, you can get on and off as many times as you want, so you could explore several towns. Even with the more restricted reserved Bernina Express tickets, I believe you can make some stops or get off before Tirano and buy the much cheaper regular tickets for the next day.

Tirano is not often recommended as a town most would want to overnight in.

Further along the route and on the shoreline of Lake Como is COLICO. Colico might be fine for a couple nights and it’s about 1-1.5 hours away from Tirano—if it’s reachable for you. Colico also has ferry service to Varenna and from Varenna you can continue by ferry to any number of towns on Lake Como— including Lecco.
Lecco works also, if it’s reachable for you. Lecco is popular with Italians visiting Lake Como.
In Switzerland, PONTRESINA is a popular place for those overnighting and has hiking and a scenic gondola. It’s just a few miles out of St. Moritz and is on the route of the Bernina Express train.

Good luck!