In the early days there were 10 return flights all designed to try and take market share from BA and BMI. Then Easyjet started up and competition became fierce with prices across all the airlines falling. Great for the consumer but the capacity was too great and yields suffered. FR changed their Scotland strategy in that they centred their European city destinations on EDI and the sun spots on PIK. The UK internal flights just didn't bring the returns so they were stopped. In fact the only one left is PIK - LDY and with load factors of around 55% not sure how safe that one is. The train might have taken a few passengers but as it is still expensive and 4.5 hours I doubt if it took so many as to cause FR to drop the STN flights. Bigger profits on the sun routes.