In spite of what you're told in ZRH you will get a full refund of the train fare plus any other reasonable expenses such as food. Having been in a similar situation I found the refund was easy to claim and handled in a timely manner. So just do what you have to do and keep all the receipts. And, if you're 'lucky' your flight from GVA will be over 20 mins late so you can claim compensation. As others have said it's a beautiful train ride just relax and make the most of it.