Last week I travelled to Aberdovey from Newtown and used the TVM to purchase a Day return fare used my Debit Card . I noticed there was a tab for Permit to Travel available on the screen and presume it is if you want to pay Cash and the machine only takes Cards . In the past I have not given it much thought . I would normally just get on board if I want to pay cash or buy a Rover ticket as neither available from the TVM , or should I always get the permit if one is available? There is no indication anywhere at the station that I can see that such a course of action is required