Adding Railcard Discount Subsequently

[LondonJohn]

If a journey from A to B in standard class is £30 And a journey from A to B in First Class with a railcard is £31 can you buy the former ticket and subsequently within ticket validity buy a railcard and then pay an excess fare of £1 and travel in First Class for the return leg of the journey?

 

[CyrusWuff]

Railcard discounts only apply to upgrades when the original ticket was discounted I'm afraid, so the excess to pay would be the difference between the sum of the appropriate undiscounted Single fares and the price you've already paid (or the full difference between the appropriate Standard and First Class Returns, where cheaper). Reference: https://www.nationalrail.co.uk/times_fares/ticket_types/46557.aspx

To give a worked example:

Travelling from Victoria to Brighton at the time an Off-Peak Day Return (CDR) is valid. The CDR is £29.40, First Class Off-Peak Day Return (FCR) is £44.10, Off-Peak Day Single (CDS) is £29.30 and First Class Single from Brighton back to Victoria is £41.30.

Working out the excess based on the Singles gives us £29.30 + £41.30 - £29.40 = £41.20, compared to an excess for both directions at £44.10 - £29.40 = £14.70.

Whether the Ticket Office at Brighton would be willing to sell the cheaper excess remains to be seen, however!