Doctor learnt about hospital transport (7)
I believe the answer is:
enthral
'transport' is the definition.
(I know that transport can be written as enthral)
'doctor learnt about hospital' is the wordplay.
'doctor' indicates anagramming the letters.
'about' is an insertion indicator.
'hospital' becomes 'h' (abbreviation for hospital on maps).
'learnt' is an anagram of 'entral'.
'entral' going around 'h' is 'ENTHRAL'.
(Other definitions for enthral that I've seen before include "Fascinate - grip" , "Delight - transport" , "Entrance" , "be captivating?" , "Totally fascinate" .)