Originally Posted by
stut
Strictly speaking, if you book a cheap ticket from Edinburgh (Waverley - this is the main station, but the name only appears locally) then you are not allowed to board at Haymarket. The enforcement of this may vary (and anyway, you can easily just buy a ticket to the next stop to get you through the barriers).
If all else fails, and you're running really late, the next stop for the East Coast Aberdeen train is Inverkeithing, the other side of the Forth Bridge. It calls here 15 minutes after Haymarket - this is a 20 minute taxi ride from the airport.
Book the ticket from Edinburgh, rather than Edinburgh Waverley or Edinburgh Haymarket. You can use it at either - I do this all the time, and there's never any problem. Also, the East Coast website discounts their own fares, and allows you to select your seat online.