I have reserved first class seats on panoramic train on golden pass but want to buy 2nd class saver pass. Somewhere on this site I read I can just upgrade for that portion of the trip. Is this true and how much$ does it cost. Ken where are you, you helped me before!!
According to the Swiss Rail site (http://rail.ch), the first class fare on the Golden Pass panoramic train (Interlaken to Montreux) is 84 CHF, second class is 49 CHF. So you would have to pay that difference at any Swiss rail station prior to the day you have reservations.