IS included-trains run nearly ev hour and NO REServ are needed (I guess not even possible, except for large groups, schoolclasses and the like).

BUT the tipical tourist out for the trip of her lifetime often feels this is too lowgraded, so the Rhaetische Bahn have cleverly (thats what the Swiss can do very well) also put on a few fancy cars with ´personal service´ and a whopping supplmt to pay-that should be REServed as of course no standees-do that, if still so wished and you have come after the shellshock of how ikspinsif Swiss is, whilst there at any counter. A few days advance is enough-unless there is also a giant Japanese tourgroup chartering this whole car-but in that case you too late now also.

I see you state to be OZzie-then you cannot use INterRail (unless you have settled here in EUR for some time and have proof for it)-but maybe you only mean this app.

Onward is by TreNord in ITaly-a strike prone country in its railways and transportations.

If you want to make a reservation at the Bernina Express you can make it here. You enter Interrail/Eurail as reduction and then you only pay the reservation fee for the seat. If you book directly at RhB then you don't have to pay the 2 EUR fee that Interrail/Eurail charges per reservation.

https://shop.rhb.ch/en/

You can also use the regional trains on the Bernina Express line. Then there is no mandatory reservation.

You can read more about the different scenic trains in Switzerland here:

https://www.swissactivities.com/en-ch/panoramic-trains-in-switzerland/

I don't see any warnings in my app that it is not included. Could you please check if there's an app update and then try again? If you then still see a warning that it's not included, could you then please post a screenshot of that, also showing the exact train with date and departure time?