Hello Suzucong86
You are welcome to bring luggage and skis in a reasonable amount with you on the Swiss trains. On some trains, there are special ski shelves; in addition, the train to Visp offers a lot of baggage space in the family coach, designated as FA on the departure board. However, for safety reasons, luggage must not block doors.
I suggest you to travel light-weight and to use back-packs to have your hands free, which eases changing of trains. Back-packs can also be easily stored between the seats near you.
Kind regards,
Roland