Effect of Service Priority and Resource Synchronization Choices on Landside Terminal Queues: Exact Analysis and Approximations

Abstract

With the growth of ocean transport and with increasing vessel sizes, managing congestion at the landside of container terminals has become a major challenge. A terminal landside handles containers that arrive or depart via train or truck. Large terminals have to handle thousands of trucks and dozens of trains per day. As trains run on fixed schedule, their containers are prioritized in stacking and internal transport handling. This has consequences for the service of other modes, which might be subject to delays. We analyze the dynamic interactions between the landside resources using a stochastic stylized semi-open queuing network model with bulk arrivals, shared resources, and multi-class containers. We use the theory of regenerative processes and Markov chain analysis to analyze the network. The proposed network solution algorithm works for large-scale systems and yields sufficiently accurate estimates for performance measurement. The model can capture priority service for containers at shared resources (such as stack cranes), while preserving strict handling priorities. The model is used to explore the choice of different internal transport vehicles (coupled versus decoupled operations at stack and train gantry cranes) to understand the effect on delays. Our results show that decoupled transport resources can mitigate both the delays of containers that arrive by trucks and by trains. When train arrival rates are low, prioritizing the handling of train containers at the stack cranes significantly reduces their delays. Further, this priority has little effect on the delays of handling external truck containers.