Research On Combination Of Linear Parameters Of Continuous Long Downslope And Small Radius Circular Curve For Passenger And Freight Railways

High-speed passenger transport and heavy freight transport are the signs and long-term development goals of railway modernization.In recent years,with the continuous increase in the length and axle load of freight trains operating on the passenger and freight railroads,the passenger and freight railroads have long,downhill,and small-radius curve combined sections and other complex line conditions.The problems of wheel-rail dynamics and vehicle stability have become increasingly prominent.In addition,when the train is braking on a continuously growing downhill and a small radius curve section,the longitudinal force between each group of vehicles and the unbalanced centrifugal force of the curve section are superimposed on each other,which will further deteriorate the overall dynamic performance of the train.The safety of long and large downhill sections will provide reasonable line parameter values and combinations for future railway design.Therefore,in-depth study of the combination of horizontal and vertical line parameters and train dynamic performance for long and large downhill and small radius curve sections The relationship between the two is very necessary.First of all,based on the method of combining statics calculation theory and dynamic simulation calculation analysis,this paper uses simulation software Simpack to establish a line model suitable for long and large downhill and small radius curve combined sections and a single-machine traction freight train dynamics simulation model.The operation of freight trains under different line conditions is simulated,and the evaluation indexes of train dynamics performance are summarized and analyzed,which lays the foundation for dynamic simulation calculation and optimization of line parameters.Secondly,according to the existing passenger and freight railway line settings and related specifications,reasonable line parameters are selected to carry out the simulation calculation of the long,large downhill and small radius curve combination section.Through simulation calculation,the calculation results of the dynamic index of freight trains during emergency braking under the condition of different line horizontal and vertical parameter combinations are obtained.The influence of line horizontal and vertical parameters and combination methods on the dynamic performance of trains is analyzed,and the value ranges and values of related parameters are obtained.The optimal linear combination method provides a reference for the design of the railway section combining continuous growth and downslope with a small radius curve in the future.Finally,use the train dynamics simulation model to calculate the dynamic parameters of the freight train hauled by a single machine at different speeds through the combined section of the vertical curve and the small radius curve,and the combined section of the limited slope and the small radius curve,and analyze and summarize the trains growth.The influence of the passing speed on the dynamic performance of the train under different line conditions in the downhill section,and then proposes the recommended values for the line parameters and the speed limit of the curve section.