A new approach to speed optimization of empty platform wagons in the Southeast region of Brazil / Uma nova abordagem para a otimização de velocidade de vagões de plataforma vazios na região Sudeste Do Brasil

Matching the demand for rail freight transportation depends on the railroad network structure and the availability of the rolling stock, locomotives and wagons. The distribution of wagons optimization helps reduce transportation costs, and the efficient allocation of assets is essential for rail competitiveness with other means of transportation. The present study aims to develop a mathematical model for optimizing the allocation of wagons and minimizing the distribution cost, adopted as empty transit time. The model also calculates the empty transit time of wagons according to demand distribution, and reduces the necessity for rail freight assets, because it also minimizes the wagon cycle. An algorithm was developed from the characteristics related to the distribution of freight wagons, using planned cycles adjusted by the demand distribution, and mathematical modeling was performed, applying integer linear programming to minimize the empty wagon transit time in a railway company. As a result, a weighted and optimized cycle was obtained to perform the sizing of wagons and meet the transportation plan, as well as minimizing the transit time between unloading and loading of goods. The new model presents a contribution to the operation, because, in addition to directing the optimal distribution of the assets using an integer linear programming algorithm, it also allows the planned wagon cycle adequacy, according to the demand of the respective period

Speed Optimization and Environmental Effect in Container Liner Shipping

The optimization models concerning the container shipping industry, either indirectly or directly, take into account a fixed transport demand hence fixed revenue. Such a conjecture excludes the freight rate’s influence upon the model’s results. In order to consider a model in which the influence of the freight rate can be evaluated, this paper consider the required service frequency for the involved route as a variable. Moreover, the model can also assess the inventory costs’ influenc