Hello Nithin
Kindly note, SwissPass and Swiss Travel Pass is not the same. You are using the Swiss Travel Pass.
It is valid on major train lines; for mountain excursions it is either not valid or grants a discount. For Jungfraujoch (which is not a mountain in fact, yet a saddle), the Swiss Travel Pass grants a 25% discount.
You can find its validity map here:
https://www.sbb.ch/en/tickets-offers/tickets/guests-abroad/swiss-travel-pass.html → section Downloads. Note the dotted line for the Jungfraujoch line.
Let us know if you need more help.
Kind regards,
Roland