VLSN Search Method Based Hubs Location and Service Frequency Determination for the Intermodal Freight Transportation Network

Abstract

This chapter attempts to study the hub location problem as well as the service frequency determination for the intermodal freight transportation network. The objectives consist of two related parts: (a) determining the optimal number and locations of the hub nodes; (b) determining the service frequencies for different transportation modes between the hubs. Nodes of the freight transportation network are classified into hubs (or hub nodes) and feeding nodes, correspondingly, the arcs consist of feeding arcs and spoke arcs. The topology of the original network is changed to convert the hub location problem to a capacitated minimum spanning tree problem (CMST) and employ the very large-scale neighborhood search (VLSN) approach to solve it. After ensuring the optimal hub number and their locations, The cumulative freight demand matrix between hubs is calculated and then an all-ornothing transportation assignment algorithm is executed on the hubs-spokes network. The service frequencies of rail and truck modes are determined based on the assigned flows of spoke arcs. The proposed formulations are tested by an experimental rail and truck freight transportation network with 89 nodes and 142 arcs. The results indicate the robustness of the VLSN algorithm, and the optimal hubs and service frequencies on spoke arcs are determined efficiently.