For many Railpassusers the Glacier and Berninaexpress are a must do when traveling arround Switzerland. Many use the fully air-conditioned “panorama trains”, some of which have very high reservation fees. The advantage of these trains is that they run directly and with a dinning service (pre booking recommened).
But
Bernina Route with Standardtrains Tirano - Pontresina - Samedan - Chur
Glacier Route with Standardtrains St.Moritz - Rheichenau/Thamis or Chur - Disentis/Muster - Andermatt - Brig or Visp - Zermatt
In summer the Rhaetian Railway use on some Routes Cabrio Cars without any roof or window the perfect car to get nice pictures. As these cars are very popular and can´t be reserved i recommend to get on them already on the starting station of the train .Here the Timetable of the Cabrio Trains
Ontop of this nice coaches they even offer historical rides without any extra cost´s than your Railpass on some Routes in Season
for example with the historical electric engine the "The Rhaetian Crocodile" between Davos and Filisur.
or the Bernina Vintage Train between Poschiavo and St.Moritz.
Thats how we (