Railway Train-set Circulation Based On Timetable Optimization

The scheme of railway train-set circulation is an important part in operation, which not only determines the number of needed rain-sets, but also influences the enablement of the yard operational plan seriously. During the process of drawing-up train operational scheme, timetable is a critical input data of planning train-set circulation. Train scheduling, train-set circulation and the yard operational are interdependent. Based on the all-in-one of transportation organization, it is essential to study the circulation of train-set while considering timetable optimization.Based on the well-known research achievements at home and abroad, this paper study the flow of timetabling based on "through" station and the circulation of train-set. To get optimal connection between train lines, the adjustment method and model for timetable based on feedback are proposed. During the process of timetabling, optimizing and adjusting, the station capacity is considerd roughly. The following components are involved:1. The character of cyclic train timetable is analyzed in detail. The mathematical model about working out cyclic train timetable based on periodic event scheduling problem (PESP) is analyzed. In China, some passenger dedicated lines with complex operation need more adaptable model. An ameliorated line programming model based on fixed departure/ arrival order is put forward for such situation. Further, the model was extended for the up-down line with the constraint of route conflict to take the capacity of throat into account. The flow of the railway network cyclic train timetable based on "through" station is proposed. And then, a case study is given out.The result demonstrates that the timetable with one hour as cycle time can partially reduce the scale of scheduling, Lingo can solve the problem quickly; Compared with timetable based on PESP, the model based on fixed departure/ arrival order which only considers the relationship between adjacent lines, needs fewer modeling time.2. To plan the circulation of train-sets based on railway "through" station with two lines at least, the characteristics of circulation for train-set is discussed in term of semicircle of train-sets'turnaround. Time tolerance a is defined to get more connection between train lines without a direction change. The model of train-set circulation is put forward and a compact connection algorithm based on time toleranceσis then designed.The result of case demonstrates that the connections between trains at terminal station is guaranteed because of timetable's equilibrium when the train lines is in pair, there are 7 connections and 6 connections at terminal station A and E separately, the connection rate is 100%; At through station D, there is 2 more connection between train lines without a direction change while the usage of compact connection algorithm based on time tolerance, but the result is not so satisfactory as a whole because of weakness of the timetable's equilibrium and the difference in quantity between railway lines, there are only 10 connections in 13 pairs without direction change, the connection rate is only 76.9%.3. The adjustment method of timetable based on the distribution of superfluous time is studied. To get the maximum adjusted quantity of train line while considering the adjustment method based on the connection with or without direction change, the related train line group is defined. If there is no adjusted space or it is hard to get the adjusted quantity when using the adjustment method, the model which can describe all the constraints between related train lines based on the feedback of train-set's circulation is more important. Then the model for feedback and adjustment is proposed to attain most connections, especially without direction change in through station between train lines. The number of arrival-departure track is also considered in the model as a posterior way.The result of the case shows that if there is no need to get big adjusted quantity, choose the adjustment method, then adjust the train lines which are the planned connection firstly; After the ultimate adjustment, there is no change for the timetable's structure and slight adjustment of travel time about train lines, and most important of all, the quality of circulation plan is improved obviously based on the station capacity satisfied, there are 7,6 connections at terminal station A and E separately, there are 13 connections, the rate of connection is 100%, especially 12 connections without direction change at through station D, and the rate reaches up to 92.3%.This paper makes efforts to study the cyclic train diagram establishment, train-set circulation and their feedback and optimization, while considering the robustnessof route assighment and the number constraint of station tracks. Hopefully, it can lay the foundation for the actionability to station working plan, and provide theoretical support to integrated train operational scheme.