Annecy is in France and Montreux in Switzerland while the border point is Annemasse.

Eurail and Swiss Travel Pass are different passes.

Eurail is valid on trains + boats on Lake Thun and Brienz. Not valid on Interlaken - Grindelwald/Lauterbrunnen (25% discount). 25-50% for mountain railways

The Swiss Travel Pass is valid on all public transportation of the country : trains, buses, trams, boats, some cable cars to villages,... 25-50% discount for mountain railways.

Not always the same discount between the two : Swiss Travel Pass more widely accepted.

There is no Eurail One-country Switzerland but you could get a Global Pass depending on your whole trip.

Usually the best combination in Switzerland is the half-fare card (120 CHF for a month) and half-fare tickets (also to Gornergrat, Jungfraujoch,...). There are half-fare Saver Day Passes for longer journeys.

Jungfraujoch (extreme example) :

- 109 CHF half-fare

- 164 CHF Eurail/Swiss Travel Pass

- 218 CHF full-fare