You probably saw this train:
https://www.railpictures.net/photo/671193/
This is actually a Swiss train. It is a SBB RABe 501, “Giruno”. Nr. 4 has been painted in a special promotional livery with the Italian flag at one end, and the Swiss on the other. This to promote the Zurich - Milano EC service where these sets mostly run. However some IC 3 (Zurich - Chur and vv.) services are also operated with Giruno’s and so this one ended up in Chur.