Longitudinal Dynamics Comparison Of Experiment And Simulation For Heavy Haul Train

With the development of world railway transportation technology,the technique of heavy haul train has received more and more attention.The excessive longitudinal impulse is important reason that restricts the development of heavy haul trains.In order to solve the problems that arise during the development of heavy haul trains,China has carried out several running and standing experiments of heavy haul trains since the 1980s.However,due to the difficulties in the test organization,high costs,and long periods,it is necessary to study the longitudinal dynamic characteristics of heavy haul trains with the methods of simulation.But,due to the lack of test data,the accuracy of the simulation system is not high,leading to deviations when studying the longitudinal impulses of heavy-duty trains,which cannot solve the root causes of the problems.Aiming at the longitudinal impulse of heavy haul trains,a heavy haul train combined simulation model of air brake system and longitudinal dynamics was established and improved according to air flow theory and locomotive dynamic braking characteristics.Take into account the many uncertainties in the actual operation of the train,Introduce the transmission efficiency correction coefficient into the air braking force of the braking system,the Electric Braking System Model for HXD1 and SS4B Locomotives were amended.the model was refined,and the simulation system precision was improved.Based on control instructions of locomotive operation of ShenHua line,the parking and operating braking condition of HXD1 Locomotives marshalling mode which isl+0,2+land SS4B Locomotives marshalling mode which is 2+2,1+1 and 2+0 were simulated.The simulation results were compared with experiment results of ShenHua line operation.Calculation result shows that:In the common air brake decompression,under different locomotives and different grouping conditions,Simulation pressure curves of train pipe and brake cylinder in each vehicle is basically consistent with the experiment results.under the conditions of parking and operating braking conditions and locomotive braking current applied,the simulation changes of coupler force were basically the same as the experiment results,the maximal coupler force experiment and simulation errors were between 0.1%and 14.2%,and the degree of anastomosis was higher;under different locomotives and different grouping conditions,the simulation of the distribution of the maximum coupler force of each vehicle are basically consistent with the experimental results;under different locomotives,different grouping conditions and different Line conditions,the simulation results of speed curves of train were basically in agreement with the experiment results.Through the longitudinal dynamic characteristics experiment and simulation results of Heavy haul trains,it can be seen that in the aspect of air brake characteristics,the transmission of the brake wave and train decompression rate of the unit train is slower than that of the combined train;the decompression rate is related to the reduction of the train pipe pressure,the locomotive type has less influence on it.In terms of longitudinal dynamics,under the 1+0 grouping mode of HXD1 locomotive,the maximum coupler force of each vehicle gradually increases with the increase of parking space,and then decreases.The maximum coupler force of each parking space in the 2+1 formation mode decreases rapidly with the increase of parking spaces,and then increases rapidly after the middle locomotive,and decreases at last.The distribution characteristics of maximum coupler force on the SS4B locomotive in 2+0 formation mode is basically the same as the 1+0 formation mode of the HXD1 locomotive.The distribution characteristics of the maximum coupler force for the 1+1 and 2+2 formation modes of the SS4B locomotive are similar to the 2+1 formation mode of the HXD1 locomotive,but it has some different things at the same time.Using the method of refining the model,the precision of heavy haul train combined simulation model of air brake system and longitudinal dynamics was improved,and provide a reliable method for the research of heavy haul train brake system and the optimization of train operation.