Train tracks (5)
I believe the answer is:
rails
'train tracks' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for rails that I've seen before include "Wading birds - dysfunctional person has come off them" , "Tracks or barriers" , "Water birds" , "Train tracks" , "Barriers of horizontal bars and supports" .)