Hello BharatParikh
Based on your itinerary and interest in scenic train journeys, here are some suggestions:
Geneva to Montreux: While not a specific scenic train, the route along Lake Geneva offers beautiful views, especially if you sit on the left side of the train for lake views.
Montreux to Zermatt: Consider taking the GoldenPass Line from Montreux to Zweisimmen, and then continue to Zermatt. This route offers panoramic views of the Swiss landscape. On the GoldenPass Line, try to sit on the right side for mountain views.
Zermatt to Interlaken: Your plan to take the Glacier Express from Zermatt to Brig is excellent. Be sure to sit on the right side for the best views of the Rhone Valley. From Brig, you can continue to Interlaken.
Interlaken to Lucerne: The Interlaken to Lucerne Express, also known as the Luzern–Interlaken Express, is a part of the GoldenPass Line. Sit on the right side for views of Lake Brienz and the surrounding mountains.
Lucerne to Geneva: You can take the Voralpen Express from Lucerne to St. Gallen, which offers scenic views, though it requires a longer journey back to Geneva. If you choose this option, sit on the left side for the best views of the rolling hills and lakes.
These suggestions maximize your scenic experiences while adhering to your route.
Enjoy your journey through Switzerland!
Greetings
RahelW