Yarn Liberal associated with major railway junction (6)
I believe the answer is:
crewel
'yarn' is the definition.
(I've seen this before)
'liberal associated with major railway junction' is the wordplay.
'liberal' becomes 'l' (abbreviation).
'associated with' says to put letters next to each other.
'major railway junction' becomes 'Crewe' (Crewe railway station is a major railway station).
'l' put after 'crewe' is 'CREWEL'.
(Other definitions for crewel that I've seen before include "Fine worsted yarn" , "Twisted yarn for tapestry or embroidery" .)