Quick railway providing uniform for servants (6)
I believe the answer is:
livery
'uniform for servants' is the definition.
'livery' can be an answer for 'servants' (I have seen 'old servants' mean 'livery' so perhaps 'servants' could also mean 'livery'). I'm not certain of the 'uniform for' bit.
'quick railway' is the wordplay.
'quick' becomes 'live' (quick can mean alive or living).
'railway' becomes 'ry' (abbreviation).
'live'+'ry'='LIVERY'
'providing' is the link.
Can you help me to learn more?
(Other definitions for livery that I've seen before include "old servants" , "Uniform, eg of guild" , "Horse maintenance" , "outfit in uniform" , "Irritable" .)