Train journalist about what moves children (6,3)
I believe the answer is:
school bus
'what moves children' is the definition.
'train journalist about' is the wordplay.
'train' becomes 'school' (I've seen this before).
'journalist' becomes 'sub' (sub-editor).
'about' is a reversal indicator.
'sub' in reverse letter order is 'bus'.
'school'+'bus'='SCHOOL BUS'
(Other definitions for school bus that I've seen before include "It carries children" , "Vehicle collecting young students" .)