With, at a price, panoramic first carriage for huge windows and see-through roof.
You would have a long-distance scenic train similar to the Glacier Express if it could be done.
There are two gauges commonly used in Switzerland 1 m narrow gauge and 1,435 mm (4 ft 8+1⁄2 in) standard gauge.
The Brünigline (the Zentralbahn in General) is 1m narrow gauge. The problem add hand is another. If you look closely you should see it: https://goo.gl/maps/VaUdLiRTHSvyTWKz6
Yes, which is why passengers had to change trains at Zweisimmen. But now it has been solved, and the train will be adjusted so it can cope with both! Amazing.
It has been a dream for 100 years:
The article is in French- apologies. But if you sanc down you will find photos of the carriage base that can change gauge.
Ingenious.
But that will not help with the Brunig Line. Did you have a look at the link to find out what the problem might be?
Any way her some videos, how the gauge change works:
This one is from three years ago https://www.youtube.com/watch?v=jJLRo4ao33k (Though it was already in use, wasn’t it ?)
Detailed view of the facility: https://www.youtube.com/watch?v=UlG50aRJuxc