Dec 20, 2017 - 6:26 AM
in reply to navis
Hi navis, and welcome to MySwissAlps!
No, the route via Landquart is a different route from Pontresina onwards, but also scenic.
If you want to see the Landwasser Viadukt, select a connection that goes via Filisur and Tiefencastel to Chur. You will get the best view of it sitting on the left, facing backwards.
Do you mean you intend to get off the train in St Moritz for a few hours? If so, it's easy to get another train from St Moritz to Zürich that goes over the Landwasser Viadukt on the way to Chur.
In your timetable search, just put "From Tirano" "To Zürich HB" "Via St. Moritz", "via Tiefencastel", and next to St Moritz put the amount of time you want to spend in St Moritz. Sunset will be a bit after 17:00, so take that into account in planning your trip.