[SandroB]

That's strange. I lived in Switzerland my whole life and don't remember having had a security / passport check for a boarding a train ever. So it's definitely not normal / regular to have this in Switzerland. Most of western Europe is part of the the Schengen Area, so there's no need for passport checks.

[HelloNurse]

Between Switzerland and Italy there are, or there used to be, foreign border agents on the train rather than checkpoints.

[prmoustache]

I've had random checks in the train over the year between Switzerland and France and Switzerland and Italy. They are definitely not regular/mandatory though.