A fuzzy railroad blocking model with genetic algorithm solution approach for Iranian railways

Abstract

Please cite this article as: M. Yaghini, M. Momeni, M. Sarmadi, M. Seyedabadi, M.M. Khoshraftar, A fuzzy railroad blocking model with genetic algorithm solution approach for Iranian Railways, Appl. Math. Modelling (2014), doi: http://dx. AbstractIn the railway, the fright car classification takes place in the terminals. This classification always imposes a remarkable delay to the movement of the cars from origin to destination. To reduce car handling, it is necessary to group various shipments together with respect to their destination in the railroad blocking plan. In this paper, for the first time, a railroad blocking model with fuzzy travel costs is proposed. In the model, the preferred fuzzy paths are determined by a fuzzy shortest path method. Then, the fuzzy model is transformed into a classic railroad blocking model. The real-life blocking problems are very large with many variables and constraints, and modeling and solving them using commercially available software is very time consuming. Therefore, a solution method based on genetic algorithm is developed. To evaluate the performance of the solution method, several simulated problems are tested and the solutions of genetic algorithm are compared with those of the CPLEX software. The results reveal the algorithm has promising accuracy and computing speed for solving the railroad blocking problem. As a case study, the proposed model for creating the Iranian railway blocking plan is utilized. Iran Railways can significantly diminish the some costs and save the time in delivering the loads.

Optimizing Train Formation Problem With Car Flow Routing and Train Routing by Benders-and-Price Approach

“…Since the TFP for railway freight transportation is at the tactical level (medium term, e.g. one month or even one year) [14], it may not be appropriate at the operational level. Hence, it is necessary to adjust the train formation plan during the actual operation according to the real-time transportation demands and other special cases, e.g., natural disasters.…”

“…A simulated annealing based heuristic algorithm was developed to solve the model. Other studies include the ant colony optimization algorithm [12], tabu search [13], genetic algorithm [14], etc.…”

Collaborative Optimization of Car-flow Organization for Freight Trains Based on Adjacent Technical Stations

“…Conversely, regions with limited capacity, where the number of cars and equipment capacity of a shunting yard is limited, use the minimum dwell time of cars at the station as the objective function [6]. Yaghini [4] proposed a railway blocking model with fuzzy travel costs for railway freight costs and transformed it into a classic railway blocking model. The results showed that the method could significantly reduce the costs of transporting goods.…”

“…Beloevi [5] studied the reorganization of freight trains at technical stations and trains marshalling methods, and according to the scale of the complexity of different grouping tasks, the rational application of the elementary grouping plan, triangle grouping plan and geometric grouping plan was proposed. Although [4][5] have achieved promising results, their studies were conducted at a single technical station, and the cooperation between technical stations was neglected. This may have prevented the car-flow organization of railway freight trains from being optimized at the railway network level and increased the total cost of railway freight transportation.…”

“…Optimizing the car-flow organization at a technical station can alleviate the pressure, improve the efficiency of car-flow organization, and reduce railway operating costs [3]. The existing studies are mostly limited to organization at a single technical station [4]. In reality, however, the operations of adjacent complex in the modelling of large-scale problems [7].…”