I will be traveling from Zurich airport to Zermatt. Will I be able to charge my train fare or do I need francs? I am just trying to figure how many francs I will need for my trip.
Swiss Rail accepts magnetic strip credit cards at the ticket windows. The Swiss Rail site will give your fares at rail.ch
Be aware the fares listed assume you have a half-price card. If not, just double it.
Your credit card may not work in automated ticket machines, but will work at staffed ticket windows in Swiss stations, as Michael said. We recommend getting francs from an airport ATM with your debit card, rather than pre-purchasing them at home. See also http://www.ricksteves.com/travel-tips/money.
You should just get Swiss francs from ATM's as you need them. If you have some "left over" at the end of the trip, you can use them to pay down your last hotel bill, before putting the rest on your credit card.