The need of simulation in queuing models for port logistics

Container discharge/loading and internal transfer between a containership and the storage/retrieval area on the yard of a maritime container terminal is a complex logistic process. Each container crosses all three subsystems of the terminal (i.e. quay, transfer and yard areas) and, while doing so, requires seizing and releasing both handling and transfer equipment (i.e. cranes and vehicles). This paper focuses on the integrated container transfer and storage/retrieval sub-process occurring on the yard subsystem. The objective is to assess the appropriate methodology for a reliable quantitative evaluation of some performance metrics. To this purpose, it is shown through numerical experiments based on real data that analytical queuing models are still not mature enough to replace discrete-event simulation in real-life environments.