Train and seat reservations Swiss trip

need information on trains and seat reservation for exact itinerary below:

1. From interlaken to Zermatt, klein matterhorn and back: I have swiss travel pass and read that glacier express requires seat reservation. can someone guide where to board glacier express from? which site will enable seat reservation? I tried SBB online site but it does not show glacier express.

2. from interlaken to mount titlis and back: does this route need any seat reservation in advance? both for train journeys upto engelberg and cable cars to the top of Mt. Titlis?

3. On trip from Interlaken to Rigi. which trains to take? are they free for swiss travel pass?

4. can glacier 3000 and gruyeres be covered on same day?

Welcome to MySwissAlps ryp1980!

In general it's good to know that train schedules can be found in the timetable, and seat reservations are only required for a few tourist trains.

1. You won't travel on the Glacier Express that day. The express trains only cover Visp to Zermatt in the afternoon, and it would not make sense to pay the rather expensive surcharge for that short ride. There are plenty of regular trains.

2. No reservations needed here.

3. Yes, this trip is free. Please see the map.

4. Please see the timetable I linked to. I think it can be done if you don't mind a long day.