Hello man
We cannot help you here as the Golden Pass is not operated by SBB yet MOB. You would have to contact MOB.
Kindly contact:
Railcenter MOBCP 14261820 MontreuxPHONE: [+41 21 989 81 90](tel:+41 21 989 81 90)EMAIL: info@mob.ch
I can imagine the error appears as currently, there are no GXP trains running between Interlaken Ost and Zweisimmen due to a technical issue with the new carriage.
Best regards,
Roland