Research On Optimization And Adjustment Of High-speed Railway EMU Scheduling Based On Efficiency Improvement

As an important facility and equipment resource in high-speed railways,EMUs are the only type of passenger carrier currently used in Chinese high-speed railways,and also the ultimate carrier for the implementation of the train timetable,which is essential for the passenger high speed rail network.With the further expansion of the high-speed railway network,the number of EMUs engaged in operators will continue to increase,and also the actual operating environment of EMUs will changing.Therefore,how to use EMU resources rationally in the new environment has become a scientific problem concerned by the railway company.This paper aims to improve the efficiency of EMU operation and reduce transportation costs,from the aspects of strengthening the use and maintenance management of EMUs,enhancing emergency response capabilities,and improving the organization level of high-speed railway transportation,study the issues related to the optimization and adjustment of EMU scheduling.Finally to realize the rapidly and automatically optimize and adjust the EMU scheduling,reduce the workload of the dispatcher,and provide an effective auxiliary reference for the actual production and operation activities.The main work of this paper is as follows:(1)Based on the differences between the management of railway transportation organizations in China and abroad,systematically sort out and summarize the research literature related to the optimization and adjustment of EMU scheduling(and other related fields).Combining with the actual background of the high-speed railway transportation,it points out that the existing research literature which needs in-depth discussion and gives relatively lacking research points.Based on this,a theoretical method for modeling and solving problems of the EMU scheduling in line with the current new environment is proposed.(2)Clarify the basic concept of the EMU scheduling problem in this paper,and analyze several major influencing factors related to the EMU scheduling optimization problem from the perspective of efficiency improvement,including train operation plan,train timetable,maintenance requirements,application mode,and the layout of the depot,etc.Combined with the existing research literature,analyze two popular modeling methods that are the multitraveling salesman problem-based modeling method and the multi-commodity network flow problem-based modeling method.The modeling methods of the two methods and also their solving algorithms are introduced,which pave the way for the modeling and solving of subsequent problems.In addition,a detailed analysis of the problem considered in this paper is given,and also how to use the multi-commodity network flow theory to build a connection network based on trip sequences is described in detail.(3)Under the premise of determining the layout of the depot and their capacity settings,EMU operating modes,combined with the maintenance requirements and other high-speed railway transportation organization restrictions,from the perspective of improving the efficiency of EMU utilization and reducing operating costs,a mixed integer linear programming model contains composition changes based on trip sequences is proposed to reduce the comprehensive operating cost and the total deadheading mileage.According to the characteristics of the established model,an iterative optimization algorithm framework is designed in this paper,which can rapidly and automatically generate a high-quality EMU scheduling considering the daily maintenance constraints.Finally,real-life instances are used to verify the effectiveness of the proposed model and method.(4)Taking the needs of the reconstruction and expansion or new construction of the depot in the current high-speed railway network as research background,a two-stage method is proposed to discuss the joint optimization problem between depot location,capacity and EMU scheduling with maintenance requirements.Based on the expansion of the EMU connection network,a multi-objective(construction cost,operating cost,etc.)mixed linear integer programming model that considers various practical operating constraints is established.A decomposition optimization algorithm is designed to solve this problem due to the model further expands after introducing the relevant variables of the depot.Finally,a series of examples based on the real-life scenarios verify the effectiveness of the proposed model and method.(5)Discuss the EMU rescheduling problem,that is,adjust the corresponding EMU schedule based on the adjusted train timetable when disruptions happened in the high-speed railway network.A two-stage mixed-integer linear programming model is presented considering all kinds of actual operating constraints and daily maintenance requirements with the goal of minimizing the deviating from the original EMU scheduling,the canceled trip,the inventory imbalance,and the extra deadheading trips.The proposed methodology is tested on several instances based on the Chinese high-speed railway,and the numerical experiments show satisfactory results for all kinds of operational scenarios.