Can I take skis in ski bag on trains from Geneva to zermatt?

Yes, and in each coach, there are ski racks at made for this purpose. Or simply store your skis on the hat rack.

Kind regards,
Roland

RolandP thank you so much. Big relief having this confirmation. Very excited about our first ski trip to Zermatt.

You are welcome.

I looked for an image to show you how they do look like. See the picture.

You can fold them down if needed.
On double-deck trains, on the lower deck, they are near the baggage shelves.

Kind regards,
Roland