Apr 8, 2018 - 7:13 PM
in reply to CJ5
Yes, you will almost certainly need to change trains in Domodossola. The timetable will tell you what the connections are on the train you decide to take. There will for most likely at least be one more change in Brig.
You show your Swiss Travel Pass (not a Swiss Pass as that is something else) to train staff when asked on the train. Before Domodossola show the ticket from Milan. After Domodossola you can just show the Swiss Travel Pass.