Called for a crosspiece (4)
I believe the answer is:
rung
I believe this is a double definition.
'called' is the first definition.
(I've seen this before)
'a crosspiece' is the second definition.
(rung is a kind of crosspiece)
'for' is the link.
(Other definitions for rung that I've seen before include "support for foot" , "Horizontal bar in ladder" , "Step up the ladder - called for" , "Level in a hierarchy" , "Telephoned" .)