Where the opportunity to purchase a ticket exists at the station before boarding the train then the passenger must purchase a ticket for their entire journey. If a passenger chooses not to buy their ticket when they have the opportunity to do so and purchases their ticket on the train then they will be charged the full standard open single or return fare, irrespective of the day and time of travel.
Where there is no ticket office or ticket machine then the passenger may purchase a ticket on the train. In these circumstances the passenger will be charged the appropriate fare for the journey that is being undertaken taking into account the day and time of travel.