Optimal train formation plan for un-unified tonnage train on rail network of port radiation area

Rail sections having different tonnage of traction is one of the important factors that impact the implement of freight train planning,and causes couple of trains running on theis routes underloading or dropping off blocks in the intermeidate swtching yards.This paper mainly study un-unified tonnage train formation problem on network,and classify strategies according to the sufficient conditions to reduce the number of comparison,rapidly obtain the optimal result.In the strategy cost structure analysis,all factors have been taken into consider,such as locomotive cost which is variable with the pulling mile,penalty cost of light load train wasting line and traction capacity etc.The frequency of trains is firstly considered into the calculation of strategy cost.Finally,a model is constructed for the train formation problem,and the train decreases tonnage on its route base on the entire network.The model not only obtain optimal switch yards for drop off cars but also selects the appropriate strategy according to traffic flow.A example is given to evaluate the effective and efficiency to this method.