Part of container train still (5)
I believe the answer is:
inert
'still' is the definition.
(not moving)
'part of container train' is the wordplay.
'part of' indicates a hidden word.
'INERT' can be found hidden inside 'container train'.
(Other definitions for inert that I've seen before include "Disinclined to act" , "Motionless or lifeless" , "Incapable of acting, like some gas" , "Lifeless, without power to move or act" , "(Chem.) not reactive" .)