Optimization Of The Connecting And The Robustness Of High-speed Railway Timetable Considering High Density Of Trains

Under the condition of the large scale network operation of the high-speed railway,both of the quantity and the type of the passenger demand show major growth,which make the supplement of the railway capacity,especially in the busy area consisting of complicated train routes,face serious challenge.In order to provide enough passenger transportation product which satisfies particular product structure under a certain market demand as well as ensure the punctuality quality of the transportation service,railway company needs to aim to operating trains with high density and make full use of the efficient transportation capacity of the current railway fixed facility,guarantee the stability of the running of the train and reduce the operation cost associated with the usage of the mobile equipment as much as possible.Timetable not only describes the exact number of the trains operated within a certain area,it reflects directly the efficiency of the operation of the trains and its robustness,therefore it has important theoretic and practical significance to integrate the timetable robustness into the optimization of the timetable capacity after studying the improving of the timetable robustness and the timetable capacity with an aim of operating trains of high density under a busy demand.Besides,it also has great realistic significance to coordinate the connecting of EMU considering maintenance with the optimization of timetables in order to reduce the mobile equipment cost.The main research in this paper is as follows:(1)A recovery-to-optimality robust timetabling model with flexible timetable structure considering the overtaking limitation is constructed:a combined headway buffer time fine-tuning method with a flexible structure is designed.To ensure train's running quality in disturbance,the method to evaluatie the recovery-to-optimality robustness of the timetable is proposed based on the construction of the complete space of the timetable structure transformation considering the overtaking limitation in delay propagation.Test case verifies that the proposed method could effectively balance the timetable efficiency and recovery-to-optimality robustness in complex train routes.The superiority of the proposed method with flexible timetable structure is shown compared with the static recoverable robust model with predefined timetable structure.This research provides basis for studying timetable robustness and research(3),which studying timetable robustness with complex delay conditions,under the aim of operating trains with high density.(2)A timetable capacity optimization model of the high-speed railway network considering the ratio of mixed train grade(stopping pattern)is constructed:The optimization of the timetable capacity is abstracted into the maximum independent set of the space-time paths in the space-time network.Different train speed or stopping pattern corresponds to a certain passenger demand.In order to meet a certain product structure,the ratios of different type of trains are considered in the optimization of the timetable capacity.An efficient branch and bound method based on the optimization of the maximum independent path subset is proposed.Test cases show the proposed method could efficiently balance the efficiency and the timetable capacity when considering the ratios of trains and has superiority over the general method for the maximum independent set.This research provides basis for studying timetable capacity considering product structure and research(3),which studying the timetable capacity considering robustness,under the aim of operating trains with high density.(3)An optimization model for coordinating the capacity and the recovery-to-optimality robustness of the timetable under the condition of the successive delay is constructed:The increase of the timetable capacity would influence the stability of the train operated.Based on an improved dynamic programming method,this paper optimizes the recovery-to-optimality robustness of the timetable while optimizing the timetable capacity.Since the disturbance in the interrelated train routes with high density are more complicated,this paper deals with the robustness considering successive delay.The robustness with successive delay is also determined based on the construction of the complete space of the transforming of the timetable structure.Test cases verify the effectiveness of the proposed method for optimizing the timetable capacity while coordinating the recovery-to-optimality robustness of the timetable when considering the successive delay through the timetable structure optimization.The bases of this research are research(1)and(2).(4)An optimization model for coordinating the timetable structure and its optimal EMU connecting based on the checking of the connecting relationship lower bound is constructed:The problem is described using space-time connecting network.The algorithm for coordinating the optimization of the timetable structure and the EMU connecting is designed including adjusting the timetable structure and the connecting relationship.The algorithm for computing the lower bound of the EMU connecting relationship with a certain timetable structure is designed,which provide information for determining whether to apply the connecting transforming under a certain timetable structure in order to improve the computing effectiveness.The lower bound also provides a basis for transforming the connecting relationship.The effectiveness of the proposed method is verified in test cases compared with the ordinary separated method.This research provides efficient solution method for optimizing mobile equipment cost under the aim of operating trains with high density.The solution strategy of this research is also able to provide a means for the coordination optimization of the research(1),(2)and this research under the aim of operating trains with high density.