The easiest route is :

- Como S. Giovanni - Monza 08:36 - 09:06

- Monza - Sondrio 09:32 - 11:20

- Sondrio - Tirano bus (pass valid) about 11:25 - 12:05

Trains run hourly, this is just an example.

The entire summer timetable for Italian trains hasn't been published yet. There will be engineering works between Sondrio and Tirano between June and September so you'll need to take a rail replacement bus. Everything will be well organized.

If you were to travel via Bellinzona and Thusis, you'll simply do the Bernina Express route the other way around Btw don't book seat reservations on the Bernina Express (19 CHF). It's a waste of money. Simply take the reservation-free first coaches on the Bernina Express (with pull-down windows compared to the panoramic cars) or hourly regional trains. All trains take the same route

Bus 5950 runs daily in high season, weekends outside that Lugano - Tirano  departing 10 am, arr 1pm.

Rail passes are valid but reservations are necessary.

www.berninaexpress.ch

Thank you for this helpful info! Can we catch the Bellinzona bus to Thusis at the Bellinzona train station, or is there a separate bus station that we must get to? I wasn’t able to tell from their website. 

Ik heb hier ook een vraag over. Ik kom op 30 juni aan vanuit Chur naar Tirano met de Bernina express. Ik wil daarna metbde trein naar Milaan, wat 2.5 uur zou duren maar ik zie dat je dan wordt omgeleid en dat het 8 5 uur duurt. Zie foto's.  Zijn er werkzaamheden aan het spoor? 

Het antwoord is al gegeven. Er zijn werkzaamheden tussen Tirano en Sondrio en de dienstregeling is nog niet gepubliceerd. Bovendien is het geen goed idee om de rail planner app te gebruiken voor de planning - die is onbetrouwbaar. Voor Italië kijk je het beste op www.trenitalia.com - de Italiaanse zomerdienstregeling zal daar het eerste verschijnen.

Dankuwel voor de info! 

@SommerS buses always depart from the train station in Switzerland. But you'll need to pay 43 CHF one-way for the Bellinzona - Thusis bus

It'll be free and quicker via Sondrio but it's as you wish :)

Swiss experts may need to confirm this but I think the lead unit on the Bernina Express is an Allegra so the windows don’t open. Other local trains have an Allegra leading with older carriages behind where you can open the windows. In high summer there are open carriages at the back. If you travel in them wrap up well as it’s a lot colder at the top of the pass. 

Allegra trains have pull-down windows :)

It's indeed quite rare for a new train

I'm not sure about Capricorn trains though but they do not run on the Bernina Railway, they're replacing older coaches between Landquart, Davos and St. Moritz (Vereina line).

Thank you, thibcabe! This is very helpful. However, I don’t think my Eurail pass covers bus travel, and I can’t find any trains going from Como to Monza and Sondrio with my pass. Do you have other information? Is it okay to purchase bus tickets to Tirano from Como on the day of, or are reservations required? There are five in my family.

Thanks again for your helpful information!

The direct bus between Lugano and Tirano is covered with your Interrail/Eurail Pass. You need a seat reservation though (19 CHF if I'm right so a bit too expensive)

The rail replacement bus between Sondrio and Tirano is covered too. No reservation needed. Usually this route is done by train but there are engineering works this summer.

When I've written coaches I meant train carriages :)

The summer timetable for Italian trains hasn't been published yet. Trenitalia is always late with that. It shouldn't change much anyway apart for the mentioned engineering works. Don't worry :)

Here is what I've written 2 days ago :)

"The easiest route is :

- Como S. Giovanni - Monza 08:36 - 09:06

- Monza - Sondrio 09:32 - 11:20

- Sondrio - Tirano rail replacement bus (pass valid) about 11:25 - 12:05

Trains run hourly, this is just an example."

No reservations needed whatsoever for this route.

Thank you! Okay, that explains why nothing comes up when I search for trains from Como to Monza, Sondrio. I appreciate your help!