Daft travelling by rail while getting the hang of the toot (5,8)
I believe the answer is:
potty training
'rail while getting the hang of the toot' is the definition.
I can't tell whether this defines the answer.
'daft travelling' is the wordplay.
'daft' becomes 'potty' (I've seen this in another clue).
'travelling' becomes 'training' (I am not sure about this - if you are sure you should believe this answer much more).
'potty'+'training'='POTTY-TRAINING'
'by' is the link.
Can you help me to learn more?
(Other definitions for potty training that I've seen before include "Behavioural lessons for the very young" , "Post-nappy education?" .)