Hello @Ck1
Thank you for your query.
The moderation team answers questions within 24 hours. For urgent queries, we recommend you to call us under the following telephone number: +41 (0)848 44 66 88 (CHF 0.08/min.) or go to a SBB ticket counter.
Normal price tickets are normally (unless they are regional tickets) valid for one journey throughout the day.
Kind regards,
FatimaH