solving railway line planning problems using a decomposition algorithm

the passenger line planning is a process of strategic long-term decision-making problem in the field of railway passenger planning. a line is a route between starting point and destination with certain stops, which has a certain frequency of train schedule. a new solution based on decomposition algorithm has been proposed in this paper, which is defined in a master problem and two sub problems. since the solution provided by decomposition algorithm is not of the integer number type, a heuristic algorithm has been proposed for converting the results to integer numbers. the objective function for the line planning problem in this article is to maximize the number of direct passengers. results on the proposed solution method, for the test problems, are compared to those of solutions generated via cplex software. results show that the proposed solution method has high performance and accuracy. as a case study, optimized passenger railway lines in iranian railway have been determined using the proposed algorithm.