Mar 25, 2015 - 9:26 AM
You don't need a pass number to book seats. You can simply book the seats, and it's up to you to also have a rail pass or ticket at hand when you board the train. Did you read about that on our website or somewhere else?
Note that only a few trains require seat reservations. Details can be found here.
Your Swiss Travel Pass can be purchased online or in Switzerland. Online is cheaper as you can see here. You can purchase the reservations along with the pass, but as said, reservations and passes are independent so you can also order separately if you prefer.
Enjoy your stay in Switzerland!