Research On The Wagon-flow Allocation Based On The Multicommodity Flow Method In Bidirectional Marshalling Station

Marshalling station is an important part of the railway transport network.The rational allocation of departure train’s wagon flow in marshalling station is of great significance for improving the transportation efficiency of the entire road network.In this paper,the bidirectional three-stage seven-field tandem marshalling station with an exchange field is studied.Based on the multicommodity flow method,the flow allocating problem of bidirectional marshalling station is transformed into the minimum cost and maximum flow problem of multicommodity flow network.By solving the multicommodity flow network,the train wagon flow allocation of depature trains is finally obtained.Firstly,the relevant knowledge of the marshalling station was reviewed,mainly including the classification and layout analysis of marshalling stations,the analysis of the operation process of traffic flow technology,the main contents of the station working plan,and the main research contents of marshalling station distribution problem and its existing difficulties.Secondly,the problem of multicommodity flow is introduced,and the relationship between the multicommodity flow and the network flow of marshalling station is analyzed.According to the characteristics of wagon flow allocation process in bidirectional marshalling station,the starting and ending points of traffic flow technical operations and the starting and ending points of special waiting time are selected as nodes of the network chart.Then,the related nodes are connected,and the edges between the two nodes are used to express the wagon flow technical operation process or the wagon flow waiting process,thereby the wagon flow allocation process of bidirectional marshalling stations is abstracted into a multicommodity flow network.And the complex index and directed edge complex parameters of nodes are determined.Thirdly,the constraints such as wagon flow continuity constraints,full axis constraints,timely departure constraints,arrival line utilization constraints,using shunting locomotive constraints,and exchange wagon operation constraints in the marshalling station distribution process are converted into constraints in the multicommodity flow network.Based on the premise that the number of starting trains is the largest,the time required for the trains to complete the technical operations is as short as possible,and a bidirectional marshalling station allocation model based on a multicommodity flow network is finally obtained,and the model is analyzed.Finally,based on the multicommodity flow method,a special calculation rule for composite indicators of multicommodity flow network in the wagon flow allocation process is proposed.Based on the multicommodity flow network,the disassembly and marshalling time of the train and the initial flow of the departing train are determined.the flow increase chain of the disintegration process of each arriving train and the flow increase chain of the marshalling process of the departing train are found,and the composite index of each node on the flow increase chain is calculated.Then according to the marshalling needs of the departing trains,the marshalling contents of the exchange trains,the disassembly and marshalling time were determined,and the relatively optimal distribution scheme,the operation plan of the shunting locomotive,and the arrival and departure line of the bidirectional marshalling station were obtained.At the same time,the algorithm was optimized and analyzed.Finally,the validity of the model and algorithm is verified by an example.