Check the others have transport in (9)
I believe the answer is:
restraint
'check' is the definition.
(I've seen this before)
'others have transport in' is the wordplay.
'others' becomes 'rest' (eg the rest of a group).
'have' indicates putting letters inside.
'transport in' becomes 'train' (train is a kind of transport. I am not sure about the 'in' bit.).
'rest' enclosing 'train' is 'RESTRAINT'.
'the' acts as a link.
Can you help me to learn more?
(Other definitions for restraint that I've seen before include "Restriction, limit" , "Reserve" , "Limiting device" , "Control, restriction, curtailment" , "Self-control" .)