Crossword Genius

Loco and carriages show how to go (5-5)

Ross

I believe the answer is:

potty-train

'show how to go' is the definition.
(show a child how to 'go')

'loco and carriages' is the wordplay.
'loco' becomes 'potty' (both can informally mean mad).
'and' is a charade indicator (letters next to each other).
'carriages' becomes 'train' (train carriages).
'potty'+'train'='POTTY-TRAIN'

I've seen this clue in The Guardian.
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