How does the Swiss Family Card work?
You simply need to take it along while traveling with your Swiss Travel System rail pass. That's all you need to enjoy free traveling for your children.
You need to make sure that the Swiss Family Card is valid before you start traveling. See the card for details on how to do so. You usually need to fill out the names of the parent(s), the names of the children, and their birth dates.
Traveling with the Swiss Family Card
Once you have a valid Swiss Family Card and Swiss Travel System rail pass, you can use them to travel. The Swiss Family Card is valid where and when your rail pass is valid. Validity of the Swiss Family Card ends when validity of the rail pass ends.
On board the train
Once you're on board, you will need to present your rail pass and the Swiss Family Card to ticket controllers upon request. The controller may want to check your passport as well, to make sure you're the owner of the presented pass and the parent of the children.