So the main disruption at the moment is the Gotthard Base Tunnel being closed. All trains are diverted via the old scenic railway and take exactly an hour longer. Otherwise no issues :)

Reservations are only mandatory on the Italian leg of the EC (Chiasso - Milan), they may not be available on ÖBB due to the above disruption. Seat reservations aren't really a thing in Switzerland.

Feel free to take any route you want. I'd obviously recommend the Bernina Railway since it is my favourite Swiss railway !

Use sbb.ch or SBB App to plan your itinerary.

This is an ideal route (you can leave Mulhouse earlier and stop for a bit in Zurich, the station is right next to the river and center) :

- TER Mulhouse - Basel SBB 10:16 - 10:40

- IC3 Basel SBB - Zürich HB 11:06 - 12:00

- IC3 Zürich HB - Chur 12:07 - 13:22

- Bernina Express Chur - Tirano 13:34 - 17:59

Reservation-free carriages with pull-down windows at the front -> the way to go :)

Thanks.

Yes, I wouldn’t normally bother with seat reservations.

I had assumed that if the trains are taking an hour longer then they can’t run as many trains and hence the trains that do run are going to be more crowded.

However from what you say, it doesn’t seem to be the case?

Regarding the Bernina Railway, in your experience, have there always been vacant seats in the no-reservations-required bits of the Bernina Express (ie the front & back carriages)?

I believe the same number of trains run but double-deck carriages cannot go through the old tunnel so it took a few days to rearrange the fleet. Only on weekends trains can get quite crowded because SBB cannot run extra trains (like they usually did).

Otherwise on a Thursday outside school holidays I'd be quite surprised if the train is busy.

About the Bernina Express : the leading Allegra unit has quite a lot of seats. It wasn't an issue when I took it, even on a Saturday.

So lower capacity due to lack of double deck trains but presumably not half the number of seats?!

Of course we can just go to Basel for 11am, take a look at the 1103 to Milan and if it looks too crowded then take the 1106 instead via the Bernina….

A possible last question - if you know the answer - is how does the “Old Scenic Railway” route, being taken instead of the Gothard Base tunnel route, compare to the Bernina Route for scenery, atmosphere, etc.?

Sorry if I wasn't clear. Instead of putting those double-decker carriages on the Gotthard Line SBB is using them on other lines like Basel - Interlaken. The regular single-deck IV Einheitswagen that usually run on Basel - Interlaken have been reaffected to the Gotthard Line. So no reduction in capacity in the end.

If you take that route you might have older carriages instead of the shiny new train but that's it.

The Old Gotthard Line is scenic for sure but a lot less than the Bernina, it is a lot lower in altitude and there's a motorway next to it too... The Gotthard line runs on the floor of the valley while the Bernina crosses Alpine passes.

Above : Bernina next to the Morteratsch Glacier, max elevation 2253 m

Below : Gotthard next to Wassen Church which you can see from 3 different points, 17 km tunnel and 1000 m max elevation