As I mentioned in the overview, the train that runs into Zermatt is a private train and is therefore not covered on your Eurail or Europass. Needless to say when you switch trains in Brig from a public train to the private one, there are no signs saying "THIS IS A PRIVATE TRAIN" before you board. I boarded the train with my Europass in hand, prepared for a smooth ride to Zermatt full of wonderful scenery. What I ended up with was a nerve-wracking experience where I thought I might never see my credit card again.
I realized there was a problem when the conductor came through and someone with a Eurail pass was handing the conductor money for another ticket. I checked my wallet and found a total of 12SF (about $8). Not good. When the conductor came to me, I sheepishly handed him my Europass and he says "private train. need ticket." I explained to him in English (I know essentially NO German) that I didn't know, and only had 12SF in cash. He repeats "need ticket" and disappears into the next car.
By this time, I have visions of being charged with a huge fine that I can't afford and being stuck in a Swiss jail for weeks. Soon, the conductor returns and says "credit card". I think - oh great, problem solved, they have a machine on the train and will just charge my credit card. The guy takes my credit card and disappears again. And doesn't come back. 20 minutes later I have still not seen him and am getting nervous because I only brought one credit card and one ATM/checkcard. In another 20 minutes, the train pulls into the Zermatt station, and I still don't have my credit card. Finally, the conductor comes through and says again "Need ticket. Office". I try to ask him about my credit card, but he just walks out of the train and heads toward the offices. I follow him, still trying to talk to him, hoping that maybe someone in the office will speak better English and explain what is going on and how I can get my credit card.
When we reach the ticket office, he goes inside says something to the ticket man in German, and hands the ticket guy my credit card. By now, I am planning in my head how to make it through the next week before I go home on just my checkcard, and how I am going to bail myself out of Swiss jail in time to make it to Rome for my return flight home. Well, the train conductor leaves the booth, and the ticket guy looks at me and in terrific English says. "That was a private train. You need to buy ticket for it. I put the ticket on your Visa, okay?"
It turns out that the conductor just took my credit card to make sure I bought a ticket once the train arrived in Zermatt. Once my heartbeat slowed down and I realized what was going on, it made perfect sense. However I suggest you save yourself the trouble and either buy a ticket at the station where you change trains or have enough cash on you to buy a ticket on the train. (Though if you read this article, you won't be as stressed by your missing credit card as I was.)