Research On Releationship Between Optimizing Scheme Of Neutral Section And Train Running Time

With the increasing of railway operating speed level, neutral section has become one of the main factors which restrict train’s speed and the density of railway operation. Improper neutral section settings will increase the capacity of the overhead line system, and will severely constrain the running time of the whole lines. As a result, reasonable settings of neutral section and optimizing schema gradually get people’s attention. But actually, the electrified railway’s design mileage is very long and with complicated line condition, using existing design rules alone to do artificial arrangement is difficult to meet the demand for the global optimization and fine design. Thereby the research on optimizing schema of neutral section and work out corresponding automatic layout software has become a desperate need for the development of electric railway.Supported by the national scientific and technological support projects "Train Control and Traction Power Supply System simulation technology", and the Technology Research and Development Program of Ministry of Railways "Simulation and Assessment of the relationship between optimizing scheme of neutral section and train running time on Passenger Dedicated Lines", this article uses theoretical analysis and numerical examples, and does research on optimizing schema of neutral section. The main contents are as follows:First, different types and technical features of neutral section settings are introduced, and the technologies for running through neural section of mainstream trains in China are compared; the setting constraints which need to be followed during the design stage of neutral section are summarized according to the existing design standards of the national railway, construction standards and relevant research literature. Second, with distance as the independent variable, a train calculation model and passing neutral section model are set up; based on the models, the relationship between scheme of neutral section and train runtime is analyzed, the influences on train’s running speed and runtime by neutral section and catch-up sections after neutral section. Under the analysis of the influence on train operation by different positions of neutral section, local optimization rules are given and proved to be reasonable and effective by examples. Then, genetic algorithm is introduced in the optimizing problem of neutral section schema, neutral section’s kilometer post of each plan is taken as an individual, chromosomes of sequential list are set up; time delay of each plan is regarded as target value, and the linear stretch as the fitness function; The neutral section set constraints are taken as discriminant for fitness degree; single-point crossover and deletion mutation methods are used to build up a method of neutral section optimizing schema of electric railway based on genetic evolution.At last, software on neutral section optimizing schema of electric railway is developed based on VS2008/MFC, which is applied for the assessment of the existing lines’neutral sections and the optimization of the layout of newly built lines’neutral sections. Beijing-Tianjin intercity high-speed railway, Beijing-Shanghai high-speed rail and the Wuhan-Guangzhou high-speed rail are chosen separately as examples, to use the software for the neutral section layout optimization, which are compared with the current plans, verifying the correctness of the theory and the practicality of the program.