The Queueing UC is part of the Unloading Use Case. Therefore, it takes place after the rock crusher has read the current payload of the hauling machine. As there could be multiple hauling machines queueing up for one or more rock crushers, this UC determines the queueing position of the hauling machines. Thereby, the rock crusher assigns a QueuePriority-Number to each hauling machine. The hauling machines can determine their respective queue position accordingly. Once the QueuePriority of a hauling machine is set to 1 this Use Case ends and the Positioning Use Case starts. A sequence diagram of this UC interaction is shown in Figure 3.