What happens if I board the train without a valid ticket?

Passengers without a valid ticket pay a service surcharge of CHF 10 on board the train in addition to the ticket price according to Tariff 600.13.1

13.1 General information 
13.1.1 Passengers without a valid ticket must pay a supplement in addition to the fare or flat-rate fare. 13.1.2 The surcharge must be paid in full, even if the customer is entitled to reduced prices. It is charged for each passenger for whom the fare is payable.

Exceptions can be found below under “Are there any exceptions to the service surcharge?”