 The range of discounts available, and the price of the card, have varied since that time, but the card has always been valid for a year's unlimited frequency of use.It can be purchased by any person aged 16 or over from any staffed National Rail station or Rail Appointed Travel Agent, by completing an application form - no photographic identification or other documentation is needed to buy or use the card.It is one of a number of concessionary fare schemes available on the British railway system.