Glacier Express stops and reservations

Hello

I am a bit confused about the Glacier Express train.

1. Does this train stop at Filisur?

2 Can I make a reservation till Filisur from Brig?

3 As I can find out the whole journey has 4 sections. Is the whole journey undertaken in the same train or do we have to change the train for each section?

Thanking you all

Udayaditya

Yes it stops there. I reserved on the glacierexpress website and used a travel pass. The train is one journey but there are local trains which do the same route. You need about 4 trains to cover the journey using these. Make sure you look for GEX on the sbb.ch timetable