I fairly regularly make short journeys in the Northern penalty fare zone, purchasing my ticket before making a journey. Depending on the journey, the ticket price is rarely much more than around £5. Several stations local to me have just acquired Northern ticket machines, but they only accept cards. In addition, the ticket offices appear to be sticking to their scheduled opening hours less reliably. While I have a card, I prefer not to use it for very small transactions to avoid large amounts of clutter on my statement, I've had issues with the machine rejecting my card, and I don't always carry a card with me. I know the general consensus on here is that if you don't have a payment card, you can pay on the train, although I can't find anything referencing this in the NRCoT. But, if I do have my card on me, is there an obligation for me to use it to buy the ticket beforehand, or can I still use cash on the train? I'm rather worried that at some point I will be issued a penalty fare for this, and it sounds like it would be awfully complicated to attempt to appeal it, so I'd rather avoid it in the first place.