Supporter of the railways? (7)
I believe the answer is:
sleeper
'supporter of the railways?' is the definition.
The answer and definition can be both people as well as being singular nouns.
Perhaps there's a link between them I don't understand?
This is the entire clue.
Can you help me to learn more?
(Other definitions for sleeper that I've seen before include "Rail supporter; secret agent" , "Supportive log on railway track" , "Brace to support rail on track" , "latent spy" , "Wagon-lit" .)