I agree that 'circuit' sounds very feasible, and also sounds better to our ears.
However, from Wikipedia:
Vehicle scheduling, also called “blocking”, involves assigning vehicles to cover the trips associated with the timetable. A vehicle “block” is the schedule of travel of a vehicle for a given day, including: (1) a pull-out from the depot, (2) a sequence of trips from the timetable, (3) any dead-head trips, and (4) a pull-in back to the depot (recall the vehicle cycle from the unit on vehicle operations).
https://en.wikibooks.org/wiki/Fundamentals_of_Transportation...