First timers with a question....trying to book the Golden Pass Express from Montreux to Interlaken online. I only see where you can enter the Half Fare Card as a discount. How does one go about having the Bernese Oberland Pass also added since that will give part of the way for free on the day of travel? We were trying to get a reserved (good) seat in advance for this panoramic train. Thanks
What you should do is select "reservation only". That way you are just reserving seats. Then separately just buy a 1/2 price ticket from Montreux to Saanen on www.sbb.ch. You can even wait with buying that ticket till you are in Switzerland. In case you reconsider the pass you intend to buy.
Reservations and tickets are completely separate from each other, and are not linked. You do not even need to be already in possession of a ticket when reserving. I did the GPX yesterday with my parents. We had 4 day passes and just separately reserved our seats.