Dead Leg

In shipping, Dead Leg refers to a segment of a transportation route that is not utilized or does not have any cargo or passengers being transported. 

Dead legs are common in transportation routes that involve multiple stops or transfers of cargo or passengers. For example, a container ship may pick up cargo at one port and deliver it to another, but then have to sail empty back to the original port to pick up more cargo. This empty leg of the journey is referred to as a dead leg.