Being operated from the terminus efficiently (2-3)
I believe the answer is:
in-use
'being operated' is the definition.
(I've seen this in another clue)
'from the terminus efficiently' is the wordplay.
'from' says the answer is hidden in the clue.
'IN-USE' is hidden in the letters of 'terminus efficiently'.
(Other definitions for in-use that I've seen before include "Currently employed" , "Unavailable; busy" , "Being employed -- unavailable" , "In employment or practice" , "Engaged" .)