A few comments:
Firstly, all the railways you list can, if necessary or desired, be travelled on using regular ordinary trains. You will see the same views
1) The Bernina Express does not just travel Chur – St Moritz (see my Bernina Express mythbuster below)
2) it is the Glacier Express (not Glacial)
3) The true Golden Pass is really only Zweisimmen – Gstaad -Montreux (see my mythbuster below)
Bernina Express mythbuster
It is important to understand the difference between Bernina Express and the actual railway infrastructure that the Bernina Express trains travel on. The Bernina Railway is the railway linking St Moritz, Pontresina and Tirano, the only railway to cross the high Alps without a summit tunnel. Elsewhere the Bernina Express train travels over other routes of the Rhaetische Bahn (RhB), ie the Albula Railway.
In recent years the RhB railway company decided to make it easier for tourists by making the ‘Bernina Express’ a through train all the way from Chur to Tirano, but only half the journey is on the actual Bernina Railway, the other half of the journey is on the Albula Railway en.wikipedia.org/wiki/Albula_Railway
The Bernina Railway is the (independent until 1947) railway built separately from the rest of the Rhatische Bahn railway. There are ordinary trains on this line and short distance Bernina Express services. en.wikipedia.org/wiki/Bernina_Railway
From St Moritz to Chur via Samedan is the UNESCO World Heritage Albula railway. It has express trains once per hour St Moritz – Chur, which have large windows and special photographer’s coaches so that when you get to the famous Landwasser viaduct at Filisur you get a good view
‘Golden Pass’ mythbuster:
It will help you in your planning to understand the ‘Golden Pass’ brand.
The original Golden Pass is just the MOB railway which runs between Montreux and Zweisimmen. The Golden Pass tag was applied in the ‘Belle Epoque’ tourist era in the early 20th Century, and there was even a narrow gauge Pullman train.
When the number of tourists coming to Switzerland from outside Europe expanded dramatically in the late 20th century, it was found that tourists wanted to travel on the route linking the three ‘top’ popular Swiss holiday regions, (Lake Luzern area, Interlaken/Jungfrau area and Lake Geneva area). A through service was devised but because there are technical differences in the railway engineering the ‘Golden Pass’ service is actually three separate trains on three separate railway company’s lines:
Luzern – Interlaken (Zentralbahn, [ZB] red and white narrow gauge trains)
Interlaken – Zweisimmen (BLS railway, blue/white/green standard gauge trains)
Zweisimmen – Montreux (MOB railway, blue and white narrow gauge trains)
When this got established, to accentuate the ‘seamless’ journey, carriages on each of the three railways were painted in the Golden Pass chocolate and black livery, so even though you had to change trains twice the appearance of the vehicles helped to make the journey seem like a single journey.
A few years ago Zentralbahn replaced its trains so the old ‘GoldenPass’ carriages were scrapped and replaced with a standard type of multiple unit trains. These new trains are dubbed ‘Luzern – Interlaken Express’
As such a journey Luzern – Interlaken can be done once per hour throughout the day on the aforementioned ‘Luzern – Interlaken Express’ completely independently of any so called ‘Golden Pass’ service
New from 11 December 2022:
The long proposed direct train service Montreux – Interlaken is about to come to fruition. Innovative technology has allowed MOB and BLS railways to come up with carriages with axles that will automatically switch between narrow (1000mm) and standard (1435mm) track gauges at Zweisimmen, eliminating the need to physically change trains from a small metre gauge train to a full size BLS standard gauge train