Timetable Optimization For Sections Connected By Single-track Railway Hub Station

Currently,single-track railways still have a significant share in China’s railway transportation network,mainly serving the transportation of passengers and goods in remote mountainous areas and high-altitude regions with difficult terrain,playing an irreplaceable role in China’s railway transportation system.To improve the capacity of single-track railways,the one-stop-one-passing scheme is commonly used at stations.However,in practical operations,situations arise where both up and down trains are stopped at a hub station on the single-track railway due to technical work or cargo handling requirements,making the adjacent two sections extremely likely to become limiting sections.In addition,the multi-directional connection of single-track railway hub stations makes the types of receiving and dispatching trains more complicated,and the dispatching work in the station is more difficult.The current methods for solving the problems of meeting between up and down trains and multiple directions of traffic at hub stations on single-track railways involve manual train scheduling to seek the optimal station meeting plan.However,this method is slow and difficult to ensure the optimal result.Therefore,this thesis focuses on the optimization problems of the two sections operation diagram for bidirectional stopping trains on single-track railways and the three sections operation diagram for multiple direction traffic at adjacent hub stations,and the specific research work is as follows:(1)Discusses the theoretical foundations of compiling train operation schedules for single-track railways.Firstly,the essential elements required for the compilation of train operation schedules on single-track railways are identified.Secondly,the thesis outlines the emergence of conflicts such as overtaking,crossing and station deadlocks during the compilation process and provides methods to resolve these conflicts.Finally,the necessity and feasibility of implementing mobile block signaling on single-track railways are proposed,based on the current mismatch between railway capacity and demand.(2)Discusses the organization of train operations under different signal block systems on single-track railways hub station when both directions of trains need to stop at stations.Based on the analysis of the impact of station dwell times on train crossing plans and the constraint relationship between station intervals and dwell times,a singletrack railway timetable optimization model is proposed with the objective of minimizing the cycle time while satisfying the constraints of station intervals and dwell times.Specifically,the model seeks to make the cycle times of two adjacent sections as equal as possible,taking into account the case where the station dwell times for up and down trains are different.The automatic compilation of train timetable is realized by using Python and its built-in turtle toolkit according to the optimization method,which improves the efficiency and accuracy of compilation.Finally,an example is given to verify the reliability of the optimization modeling method,which can help dispatchers in the preparation and adjustment of daily operation train timetable.(3)Discusses the optimization of the three-sections train timetable for single-track railways.Five evaluation indicators were proposed to assess the feasibility of train crossing plans at the station.The thesis first analyzed the train crossing plans for the main line trains and branch line trains without considering angle trains.Based on the train crossing plans of main line trains,branch line trains,and different nature trains,three train crossing plans were proposed: two stops for down trains and two passes for up trains,two stops for up trains and two passes for down trains,and crossing plan for trains with different properties.Considering the meeting of angle trains at the hub station,three train crossing plans were proposed and compared comprehensively.The results show that the optimal train crossing plan for main line train and branch line trains is the two-stop for down trains and two-pass for up trains mode without considering angle trains.However,when considering angle trains at the hub station,the optimal train crossing plan for main line trains,branch line trains,and angle trains is the two-angle train crossing plan under the two-stop for up trains and two-pass for down trains mode.