" without knowing The Glazier Exoress and the Gotthard Panorama Trains are closed. "
The trains aren't 'closed' as such
You have fallen into the 'marketing trap' that I think is a big problem for Swiss railways. The two trains you mention are so 'well' marketed that occasional or first time visitors think that during periods that the 'special' trains are not running, that means the railway they travel on is closed. That is not in fact true, because all the 'famous' aka 'panoramic' aka 'scenic' trains in Switzerland run on normal railways with frequent regular trains open to all passengers and used by tourists, commuters, schoolchildren, local farmers, shoppers etc
(my personal views on the Glacier and Gotthard Panorama trains are at the bottom of this post)
Try not to focus too hard on the so called 'scenic' trains. Nearly all railways in Switzerland are scenic in some way - if you don't see high mountains you will see other icons of Switzerland such as lakes, rolling pastures, farmsteads, cows etc. - so you will rarely be disappointed with any Swiss train trip
If you get a Swiss Travel Pass, you can travel on any and all of the railway lines of the main Swiss national network, this includes any train on the so called 'Glacier Express route' (which in fact is just a normal railway with lots of normal trains services throughout the day.
Nearly all railways in Switzerland are scenic in some way, and it’s a small country so you can start anywhere you like.
A good publication to start with is:
www.bradtguides.com/sh op/europe/switzerland/ switzerland-without-a-car-3302.html
A look at this relief map will show you where the high Alps are and it shows the railways in context with the mountainous regions very well:
www.citymetric.com/sit es/default/files/artic le_body_2018/02/switze rland_without_trains.p ng
My personal views on the Glacier and Gotthard Panorama:
Gotthard Panorama Express - a personal view
This is ‘take it or leave it’ advice:
Personally I am sceptical of the attraction of the Gotthard Panorama Express. It is an attempt to keep some tourism going on the Gotthard 'mountain route' since the rest of the fast trains now go through the base tunnel. However, you see mainly valleys not high mountains. Also it is reservation obligatory and first class only.
Also, the train gets rather lonely - part of the ‘romance’ of the Gotthard route previously was that your train competed for space on the line with huge long international long-distance trains carrying 000s of passengers a day between northern and southern Europe, and those passenger trains interacted and weaved in between dozens of heavy freight trains lumbering back and forth across the Alps.
The curiosity was seeing another train high above you one minute then a few minutes later passing by your train on the same level, then perhaps seeing it again below you a few minutes after that. It is this that no longer happens as there are so few trains left on the line.
More economical might be for you to take any boat Luzern - Fluelen. Then take the train Fluelen - Erstfeld. Change at Erstfeld into the regional train that takes the same old mountain route but at no extra cost, and runs direct through to Como (and Milano)
Take care with the hyped-up marketing of the Glacier Express. It is not always the best way to 'see Switzerland'
The Glacier Express runs roughly on an East - West axis in the southern part of Switzerland, so trying to access it from further north is falling into the trap of being lured by the hyperbolic marketing of the Glacier Express. In practice the Glacier Express is just an ‘exclusive’ train on a normal railway route with plenty of other normal - non supplement , reservation-free trains on it.
To understand the above, it is worth taking a moment to understand the Glacier Express and its history:
It was created (as one train each way daily) with the notion that well-healed travellers taking long holidays in Switzerland in the ‘Belle Epoque’ era (1930s) would stay in Zermatt and then also go and stay in the other fashionable resort of the time, St Moritz. The train was named (mainly) after the Rhone Glacier which has now melted so much that you don’t see it from the train and in any case the train runs under the Rhone Glacier in a base tunnel which replaced the Furka mountain section in 1982.
Points to bear in mind about the Glacier Express:
Although the whole journey is in the mountains, a lot of it is in valleys - where you get some good views of bubbling rivers but not all the time - there are some mundane sections.
in truth there are only 4 really spectacular sections - in order West to East: the loops around Grengiols and Fiesch; Andermatt - Oberalppass - Disentis; Ruinaulta (Rheinschucht aka Rhein gorge); Albula north ramp loops and spirals Tiefencastel - Filisur - Preda
The trip is a long one - tourists can frequently be seen sleeping rather than watching the view and missing the spectacular bits anyway!
the same railway lines can be travelled using ordinary local trains which are no slower in practice due to the single track infrastructure