18. Comparison and Optimization of Automated Yard Crane Systems at Container Terminals

In this chapter, four different automated Rail-Mounted Gantry (RMG) yard crane systems – Single RMG, Twin RMG, Double RMG (DRMG) and Triple RMG (TRMG) – are compared with respect to their characteristics and performance. Furthermore, different approaches for their scheduling are presented: On the one hand, a branch-and-bound procedure for single yard block optimization which incorporates important aspects like crane interference, and on the other hand, an integrated scheduling approach which optimizes the equipment at terminal yard and waterside simultaneously, taking the interrelations with horizontal transport and quay cranes into account. Moreover, a combination of the two approaches is studied. Using a specifically designed simulation model, both the crane systems and the different scheduling approaches are extensively examined with respect to their performance and practical use, e.g. in case of disturbances. Standard priority rules (e.g. First-IN-First-OUT) serve as a benchmark here. It turns out that both approaches are advantageous compared to simple priority rules, and that the crane systems with overtaking possibility are well-adaptable, optimizable, flexible and productive. Moreover, it can be concluded that optimization aspects should already be taken into account in the terminal planning phase, in order to reach optimal productivity levels later on.