Going with those people, almost finished travelling (2,3,4)
I believe the answer is:
on the move
'travelling' is the definition.
(I've seen this before)
'going with those people almost finished' is the wordplay.
'going' becomes 'on' (both can mean functioning or activated).
'with' says to put letters next to each other.
'those people' becomes 'them' ('they' refers to a group of people).
'almost' means to remove the last letter (almost the whole word is kept).
'finished' becomes 'over' (over can mean finished or ended).
'over' with its last letter removed is 'ove'.
'on'+'them'+'ove'='ON THE MOVE'
(Another definition for on the move that I've seen is " Travelling".)