Experimental Research On Longitudinal Dynamics Of Heavy Haul Train

The development of heavy haul railway is the important measure to solve the current railway transport capacity tension in our country.However,with the length increased,the vehicle axle load and the traction weight improved of the train,the train traction force and braking force are increased,the brake wave transmit time is extended,the resulting train longitudinal force caused the vehicle off the hook,hook,derailment,accident of train longitudinal dynamics research proposed severe challenges,control has become the key problem of heavy haul train transportation development.In order to reduce the heavy haul train's longitudinal impulse caused by braking and releasing asynchronism.improve brake propagation speed and release propagation speed,this paper according to field test data from Shenhua C80 gondola car air braking system and hook buffer device as the main object of study,combined with the line file and locomotive operation record analysis of tons contrast 1 +1 +0 and 1+0 two marshalling trains,the train pipe,auxiliary air cylinder and brake cylinder pressure characteristics and the longitudinal dynamic characteristics of brake and release velocity and coupler force situation of train under the different pressure reducing conditions of common braking and releasing conditions.The calculation results show that the braking speed when the train decompression 50kPa under the 1+0 formation method is 163m/s,decompression 100kPa braking velocity is 202m/s,1 + 1+0 formation method with the same decompression the braking velocities are 193.6m/s and 233.7 m/s,improved 18.8%and 15.7%compared with 1+0 formation method.The train in the braking process,braking action along the length direction of the train has different starting braking time and brake cylinder pressure velocity inhomogeneity'.Under the mode of 1+0 formation,no matter how much the braking pressure is used for braking,with the increase of vehicle number,the piston extends time become longer,the more reduction of the train pipe pressure,the piston reaches out sooner,head and tail car start braking time difference is smaller,the average braking velocity is higher.In relief conditions,there is a time difference from the train pipe starting inflating to the brake cylinder starting exhausting,so after the train pipe began inflating for a period of time the train pipe relief curve appeared an obvious peak,the acceleration relief air cylinder begin to play the role of "local pressurization".Different reaction force will occur between the connector of the vehicle in the braking condition,to make the excess power transmit to the power shortage of the train,and produce longitudinal forces across the train,so that the braking force achieves the average.The analysis and calculation by using test data in this paper have great significance to improve the economy and safety of 10,000-ton train.