Triberg, Germany:
Schwarzwaldbahn-Erlebnispfad, Starting from the station this short hike(6,5km) has some information on the construction of the blackforest railway and some lookout points. There is also an upper section (additional 6km) if you are looking for a longer hike. In addition Triberg also has waterfalls (i have not visited those yet). (http://www.schwarzwaldbahn-erlebnispfad.de/de/startseite only in german)
Oberswil im Simmental, Switzerland:
Starting from Oberswil im Simmental there is an interesting hike (8,5km) with quite some stairs.
Proper shoes are important if you want to go up to the caves. The route also involves a 111m long suspension bridge. (https://lenk-simmental.ch/en/experiences-tours/experience-detail-page/detail/haengebruecke-leiternweide-oberwil-8 )
(https://www.okwirsindweg.ch/wanderung-simmental_erlebnisreiche_abenteuerwanderung/ only in Geman)
Instead of doing a circular hike as suggested, it is also possible to do this hike from Oberswil to Weissenburg as both have a train station. While the golden Pass trains do not stop at those station tboth of them are located along that Route.
Link regarding just the cave part: https://lenk-simmental.ch/en/experiences-tours/experience-detail-page/detail/cave-path
Mürren, Switzerland:
Hike between Mürren and Grütschalp (Train/cable car station). Grütschalp is easy to reach by cable car for Lauterbrunnen, form there it is possible to take a train to Mürren. (Both train and cable car can be taken with an interrail pass)
Also Lauterbrunnen has a lot of waterfalls that are worth visiting, just a short walk from its train station.
Davos, Switzerland:
Lots of hiking options. I did some of the ones starting directly at the youth Hostel in Davos (Höhenweg)
I also did a short hike from Davos Wiesen to Filisur (the route goes over the Wiesner Viadukt) and can be nicly combined with riding the historic train between filisur and Davos. The open wagons are nice if the weather is good.
For one day i also got me a day ticket for the cable cars up the mountains from Davos (Im the off season it is not that expensive if you have guest card arround 20CHF)
I am open for more suggestion for my next trips that are worth a short visit. I could us some recommendation for Austria. (anything to do with trains is always a pluss) Also ideas for a weekend in switzerland are always welcome (in case i have some left over days i always do a weekend trip in switzerland)
This is just of the easy to reac