Thank you for your request.
Yes this train is covered by your Swiss Travel Pass but you still must pay a supplement.
Seat reservations are compulsory on this train and can be made either by telephone or at an SBB counter of your choice.
Tel. 0848 44 66 88
(available 24/7, sometimes you may be required to wait)
or if you are calling from abroad:
+41 51 225 78 00
A seat reservation and supplement is required to travel on the Gotthard Panorama Express.
Have a nice day