The Analysis Of Train Longitudinal Impulse And Security During The Oversize Commodity Car Delivery Towing

Since the opening up and reform, the economy of China has stepped in a high speed growth period. There are more and more heavy or oversized equipments in the heavy machinery manufacturing, large ships, aerospace and nuclear industry and other industries. A lot of large-scale equipments must be transported from manufacturing base to the construction site directly. The relationship between oversize cargo and national important project is very close.The oversize commodity car that it is used to load all kinds of heavy or oversized equipments is a very special vehicle in the railway transportation. It is often added to the train to run with marshalling, the security problem is caused by the train longitudinal impulse because of the choice of its location, which is worth to concern. There are a few vehicles marshalling in the actual transportation, which does not cause a very large longitudinal impulse, but there are a lot of vehicles marshalling in the actual delivery towing, it causes a very large longitudinal impulse because of the increases of speed difference between the front portion of the vehicle and the rear of the vehicle in the transient operation, which is a dangerous working condition. For example, a well-hole wagon has once occurred derailment accident. Therefore, we should find the best choice of its location and the most dangerous occasion through the simulation analysis so that we could extend associated equipment life and reduce accidents.In this paper, by using co-simulation systems of train air brake and longitudinal dynamics which adopts the method of computer numerical simulation, we analyze the influences of the train longitudinal impulse in different marshalling and research the oversize commodity car security during running.The results show that the oversize commodity car is laid up the tail part of the train is a relative safe project. The oversize commodity car maximum coupler force keeps the low numerical value. Compared with the oversize commodity car laid up the middle part of the train in emergency braking process, the maximum compressive hook reduces63.2%, and the maximum pull hook reduces by59.2%, the location of the maximum coupler force is far away with the oversize commodity car. The most dangerous occasion is that the train which the oversize commodity is laid up the middle part of the train is emergency braking. In the actual delivery towing, when the train which the oversize commodity car is laid up the tail part of the train and two locomotives are laid up the head and the tail is running on the ramp, the location of the maximum coupler force is close to the tail part of the train and the maximum coupler force is big. It is also a dangerous occasion. The tail part of the train may derail. Therefore, the location of the oversize commodity could move forward from the tail part of the train.