Pullman track supporter (7)
I believe the answer is:
sleeper
This might be a double definition.
'pullman' is the first definition.
(I've seen this in another clue)
'track supporter' is the second definition.
The answer and definition can be both people as well as being singular nouns.
Perhaps there's an association between them I don't understand?
Can you help me to learn more?
(Other definitions for sleeper that I've seen before include "latent spy" , "An overnight train?" , "Form of transport" , "Long-inactive secret agent" , "Timber beam" .)