A Study On Longitudinal Dynamics Of Mixed Long Freight Trains

With the rapid development of the national economy, the industry volume for rail capacity requirements continue to increase, heavy transport has become the key development direction of China’s rail freight.a lot of overweight or oversize equipments, such as power equipment, chemical machinery, high pressure boilers and bridge components, requires better performance of the train which takes the task of goods transportation.The oversize commodity car is a very special vehicle in the railway transportation, It often to be added to the train to run with formation, it’s worth to concern the position of the oversize commodity car in the train formation will cause safety issues to the impact in Longitudinal of the train. So it is significance to make sure the overweight train safe and running smoothly by identifying the effective methods to reduce the maximum longitudinal force and grasping the variation of the actual train longitudinal force,In this paper, by using co-simulation systems of train air brake and longitudinal dynamics which adopts the method of computer numerical simulation, we analyzed the longitudinal impact of the overweight train, achieved the synchronous simulation of the air brake and longitudinal dynamics, it can dynamic simulation and display the whole process of train operation in real-time, it is significance to improve the cdynamics of the overweight train.The simulation analysis show that the longitudinal dynamics of the whole train depend on the launch of the overweight or oversize train and the good or bad operation synchronized performance of the master control and slave control locomotive’s. The formation of the overweight or oversize train will have impact in longitudinal. When train is launched and accelerated, the position of the oversize commodity car in the train formation will not impact the coupler force a lot; but when the train is emergency braking, to put the oversize commodity car into the center of the whole train will get lower coupler force. At last, when the train is launched and emergency braking on the same ramp, since the whole train will be impacted by the force of the ramp, so the impact in longitudinal on the ramp will be the similar to the flatness road.