That makes Pembrey wrong then.
Analysing the clue. It is clearly a double track line. Assuming the photograph is modern and taken on BR, it is taken from a droplight window, so either on a HST or hauled set (I think that only includes the sleepers, Gerald and Scottish bits at the moment). I will assume it is off the Western and not in Wales.
I think I spy a signalbox and crossing beyond the footbridge. Blair Atholl fits, so I'll try that.
--- old post above --- --- new post below ---
I'll go for Blackburn in the sweepstake then, if it isn't taken.