Green’s Dictionary of Slang

appro n.2

[rhy. sl. = approbation]

railway station.

Eve. Tel. (Dundee, Scot.) 3 Aug. 4/1: Off he goes to the ‘appro’ (‘approbation’ railway station). He takes his ‘bat and wicket’, has a chat with his brother ‘bloaters’ (‘bloater roe’ - professional), and gets into the ‘Andie Caine’.