Hello pamwinter
On most trains within Switzerland, seat reservations are not obligatory and are therefore not included in the train ticket.
Seats may be reserved in trains which are marked “R” (reservation possible), “RE” (reservation recommended) or “RR” (reservation mandatory) under “comments” in the online timetable.
Detailed information on the various booking options are available under: https://www.sbb.ch/en/travelcards-and-tickets/tickets-for-switzerland/seat-reservations.html
Seat reservations Golden Pass Panoramic and Chocolate train:
http://www.goldenpass.ch/en/goldenpass/offer/index-lines
Seat reservations Luzern-Interlaken Express:
https://www.mob.ch/en/reservation-procedure
Seat reservations Glacier Express:
https://shop.glacierexpress.ch/gex_en/
Seat reservations Bernina Express:
https://www.rhb.ch/en/panoramic-trains/bernina-express
Seat reservations Jungfrau:
http://shop.jungfrau.ch/en/tickets/bergbahn
Seat reservations Post-Bus tourist lines:
https://www.postauto.ch/en/fahrinfo-reservationen
Kind regards
ManuelaPf