Optimization model on loaded & empty car flow routing considering coordinated utilization of railway capabilities
The purpose of this study was to improve the overall passability of railways,make balanced use of all lines in the road network,cope with the increasingly volatile transportation market,and investigate the coordination and optimization model of loaded and empty car flow in consideration of the coordinated utilization of line capacity. First,the implementation mechanism of coordinated utilization of line capacity was studied. On the basis of considering flow balance constraints,empty car distribution constraints,and line capacity constraints,the coordinated utilization of railway line capacity was added. Meanwhile,the cost of use of tight lines in the optimization goals was increased. A loaded and empty car flow organization optimization model considering coordinated utilization of line capacity was constructed,so as to achieve coordinated utilization of railway lines while optimizing traffic flow routes and vacant vehicle deployment plans. Then,a Lagrange relaxation algorithm was designed to relax line capacity constraints and capacity coordination constraints,and break down the original problem into traffic flow path problems,empty vehicle deployment sub-problems,and virtual traffic flow sub-problems,so as to reduce the difficulty of problem solving. Through 5 sets of arithmetic examples,the effectiveness of the algorithm is verified. As shown by the case results,the designed Lagrange relaxation algorithm was more efficient than the commercial solution software Gurobi when solving large-scale calculations. Finally,an actual case involving 56 lines at 36 stations was designed. The solution of the algorithm took 4757.7 s,and the comprehensive cost of transportation organization was 29535803 yuan. Through analysis of the solution results,the model optimization results can reduce the number of routes with tight capacity from 17 to 12 under the premise that transportation costs only increased by 1.56％,reducing 29.4％. At the same time,empty vehicle deployment complied with the principle of nearby empty trains distribution. As revealed by research results,this model can effectively ease the tight situation of railway capacity and promote coordinated utilization of railway line capacity.
railway capacitycoordinationcar flow pathempty car distributionlagrangian relaxation algorithm
万方数据
维普
