10h30 - 10h55
Reducing Hazardous Materials Releases from Railroad Freights through Dynamic Trip Plan Policy
Abstract— Railroad transportation of hazardous materials freights is important to the North America economics that support the national’s supply chain. This paper introduces various extensions of the dynamic hazardous materials trip plan problems. The problem captures most of the operational features of a real-world railroad transportations systems that dynamically initiates a set of blocks and assigns each shipment to a single block path or multiple block paths. The dynamic hazardous materials trip plan polices have distinguishing feature that are integrating the blocking plan, and the block activation decisions. We also present a non-linear mixed integer programming formulation for each variant, and present managerial insights based on a hypothetical railroad network. The computation results reveal that the dynamic car scheduling policies are not only able to take advantage of the capacity of the network but also capable to diminish the population, and environment risks by rerouting the active blocks along the least risky train services without sacrificing the cost advantage of the railroad. The empirical results of this research illustrate that the issue of integrating the blocking plan, and the train-makeup of the hazardous materials freights must receive closer attentions.
Keywords—Dynamic car scheduling, Planning and scheduling hazardous materials freights, Integrated blocking and routing plans, airborne hazardous materials, Gaussian Plume Model, Box Model.
10h55 - 11h20
Railway Transportation of Hazmats, MILP, Multi-order, Multi-commodty Problem
Transportation of hazardous materials is one of the most significant research areas in the realm of supply chain, mainly, in North America. Most of the papers, however, have focused on the highway transportation of Hazmats. Yet, there have been some papers concentrating on the railway transportation of dangerous goods. In our paper, we are focusing on the railway transportation of both Hazmats and regular commodities. Yards and tracks are the constituents of our network. Orders are made at various nodes and are to be shipped towards destination yards. We are solving a mixed integer, multi-objective, multi-order, multi-commodity problem with constraints on both Hazmat commodities as well as regular commodities. We assume each OD order can be placed containing both regular commodity, and Hazmats pertaining to two different categories, Toxic Inhalation Hazards (TIH), and explosives which present no significant blast hazards as well as extremely insensitive explosive commodities which do not have a mass explosion hazards. Orders are to be shipped from origin yards to their destination yards using a single path or Itinerary, non-bifurcated flows. As well, we have modeled a real network using two approaches: 1) bifurcation of flows is allowed, and 2) bifurcation of flow is not allowed. Then, we have compared the results and drawn conclusions about the pros and cons of each modeling approach and viability situation of each.
11h20 - 11h45
A Practical Time Slot Management and Routing Problem in Attended Home Delivery
We describe the solution methodology to approach an attended home delivery problem faced by an Italian service provider. We propose an LNS heuristic that creates time slot tables by relying on various simulation strategies to represent customer behavior and on an integer linear program to optimize the routing of technicians.