You've already gotten good advice and I'm just going to agree with it, but my husband and I always travel First Class on trains even though we're extraordinarily cheap in many aspects of our travel. It is quieter and roomier, and when I'm sitting in a First-Class compartment watching the Alps go by and drinking bad instant coffee, I feel extraordinarily rich.

Generally it's a quiet crowd. We were once subjected to a guy who chattered in Italian the entire trip and must have said, "Ciao, ciao, ciao, bye, bye, bye" at least 8 times before he actually terminated the call- but he's part of our travel stories. And once we ended up having a nice conversation about Anglican church poliitcs with the Anglican Bishop of Aberdeen and the Orkneys, whom we met going from Aberdeen to Edinburgh.

Have a great time!