Maybe this belongs in the Three Rail Forum?

The rail network of Switzerland is one of the densest and spectacular in the world. It covers a total length of 5063 km of lines with 3652 km on international gauge 1435 mm, 1312 km on metre gauge and 68.5 km of 800 mm or 750 mm gauge.
1,435 millimeter = 4 feet, 8 1/2 inches
1,000 millimeter = 3 feet, 3.37 inches
800 millimeter = 2 feet 7 1/2 inches
750 millimeter = 2 feet 5 1/2 inches
800 millimeter = 2 feet 7 1/2 inches
750 millimeter = 2 feet 5 1/2 inches
(For comparison, the Durango and Silverton Narrow Gauge Railroad is 3 feet (914.4 millimeter) gauge.)
The bogies on the GoldenPass Express change gauge width in a matter of seconds with the passengers on board. When the train arrives from the metric gauge tracks at Zweisimmen station, the train passes over a gauge adapting ramp and the train changes gauge.
Reference:
https://youtu.be/cDkGUnqLXUk?si=eYxLDrvFWef_dcoc