Bernina: just ride in the unit hauling the panoramic coaches, views are pretty much as good
… and despite being quite modern units, they still have a few windows that can be slid down quite a bit, although I guess that might be more something for summer than for winter.
In principle I can recommend the hotel at Ospizio Bernina for a mid-journey break in that area (the restaurant at the hotel, too), although maybe less so in winter, because from the station you need to walk approximately 600 m (and 60 m height difference) along a gravel road to reach the hotel. In summer that's doable even with some reasonable amount of luggage, but in winter it might more difficult or depending on the weather outright impossible. The hotel does offer a road shuttle to a neighbouring station in that case, but it's still a bit more of a hassle.
There's another hotel directly at the station in neighbouring Alp Grüm which according to a colleague who slept there instead is nice, too, but it might be a bit more pricey.
If you want to travel along the Bernina route in one direction only, the official solution is a special express coach from between Lugano and Tirano, but (at least in summer, though) I can also recommend the railway line between Milano and Tirano, which especially alongside the Lago di Como is quite scenic. There were only two caveats:
- FS loves do the major track works during summer, and in recent years it seems they've been regularly working on that line, too. We were lucky in that we only had to take a replacement bus on the last stretch between Sondrio and Tirano (and while it did throw off our schedule a bit, thankfully it wasn't too much), but depending on which section they're working on this year, it might be a bit more hassle. Somewhat annoyingly, there's a timetable change in June and schedules plus details of any construction works for the period after the timetable change are only published relatively late (around May or so, maybe late April), so you can't do anything except hopefully having enough of a cushion in your schedule there.
- We originally wanted to go from Locarno to Monza and change there for the line to Tirano, however while some trains on that line are operated using loco-hauled coaching stock with a sufficient number of carriages, others utilise single unit EMUs, and the train we wanted to catch at Monza was completely stuffed to the gills (not sure if this was just bad luck due to some event/the good weather/… or whether it's a regular occurrence on that line in summer), so we ended up backtracking all the way to Milano in order to be sure we'd be able to get on one of the following trains. Luckily we did have enough spare time in our schedule that even in combination with 1.) above we still managed to catch the last train to Ospizio Bernina (beyond that, there still would have been one or two Postauto connections as a fallback, at the price of missing out on the Bernina train ride though of course) .
I've also had good deals in Locarno, with free passes covering the Ticino region public transport included as well.
And if you're doing e.g. a day trip to Como, using the regional trains (anything else probably isn't worth it anyway on that stretch) you only need to pay a very cheap extension ticket on the Italian side from Chiasso/the border to Como.
Just don't make the same mistake I made thinking it wasn't that far from Brig but not considering the mountain range inbetween which made for a much later arrival than expected.
Though at least Locarno – Domodossola via the Centovalli Line is also quite scenic, and Domodossola is also nice for a little stopover for lunch.
the Lotschberg mountain route on the BLS
Did that, too, and had a nice experience with the guard there – the train wasn't too full and when she saw on our Interrail travel itinerary that we were going all the way to Berne the slow way (relatively speaking), she actually let us move to the first class section of the train. Not that there's a spectacular difference on those trains, but there were slightly more comfy seats and it was a nice gesture of course.
I'm not sure how it holds up in winter because we went there in summer (it seems that for those who don't go skiing, they do some sort of annual 'visit the home of Santa Claus on top of the mountain' thing each year in December, which might or might not be interesting if you're visiting with a little kid), but the Rochers-de-Naye line from Montreux was also quite nice. We did that last summer – we originally wanted to go from Brig to Zermatt and do the Gornergrat railway, but both the line beyond Visp and the Gornergrat railway itself had just been closed due to the track damage after severe weather with flooding, and luckily the line towards Montreux was open at the time (it temporarily wasn't a few days later I think due to some more flooding), so instead we went to Rochers-de-Naye.
