Hi Traveller 17 -
I'm not quite sure whether youare asking about a trip in addition to your trip between Luzern abd Grindelwald?
That trip travels on part of the Golden Pass route. specifically, on the portion of the Golden Pass route called "The Luzern-Interlaken Express" between Luzern and Interlaken Ost, via the Brunig Pass. There is some nice scenery along that route. Once you reach Interlaken Ost, you change trains for Grindelwald. It is a side trip from the Golden Pass route.
The most scenic part of the Golden Pass Route is the part from Zweisimmen to Montreux.
To understand that, you can use this map, enter some of the city/town names above in the search box, and see where each one is on the map.
I have zoomed in a little bit so you can see Montreux.
Zoom in more and you can see the train lines. This view shows the line between Interlaken and Grindelwald.
The glacier Express runs in a completely different part of Switzerland, and is not near the places you have named. If you wish to take it, you will have to do some more traveling.
Check this link and use the map to search for various city names mentioned in this link. Then you can see where the Glacier Express runs:
This link discusses scenic trains:
www.myswissalps.com/ac tivities/scenictrips/t rain