Comparative Study On The Segmented Electro-Pneumatic Braking And Pneumatic Braking

Heavy-haul transport is the general trend of the development of railway freight transportation in the world,and it is an effective means to improve transport efficiency and economic benefits in addition,it can also reduce the cost of social logistics transportation.The heavy-haul train technology has continuously brought new challenges while helping railway construction.Although China’s pneumatic braking technology is becoming more and more perfect in many years of development,the increasing load also puts forward higher requirements for freight braking.The pure pneumatic braking system is limited by the propagation speed of air signal during braking,which will lead to the phenomenon of train braking out of synchronization,and inevitably produce a large coupler force.However,the current ECP system in foreign countries is not compatible with China’s pneumatic braking system,what’s more its application in China will face many problems such as high cost and long transformation period.In order to change this situation,the segmented electro-pneumatic braking system arises at the historic moment,which is a new type of electronically controlled pneumatic braking method based on the current railway situation of China.The application of the system only requires the installation of electronic control devices on some vehicles,which can improve the synchronization of train braking(releasing)and effectively reduce the longitudinal impulse of trains under various conditions.At the same time,it also has the characteristics of low transformation cost and perfect compatibility with the current pneumatic braking system in China.Using the TABLDSS to simulate the braking(releasing)characteristics of different trains under two braking modes,the braking capacity under various brake application conditions on flat line,the coupler force and cyclic braking on the long and steep rampways,compare the differences of braking(releasing)characteristics,braking capacity and coupler force between the two braking modes,and then analyze the superiority of the segmented electro-pneumatic braking system in improving the longitudinal dynamic performance of the train.The simulation results show that the segmented electro-pneumatic braking can effectively improve the synchronization of braking(releasing),strengthen the braking capacity,and effectively reduce the coupler force of different trains,different loads and different marshallings.In terms of the braking capacity,compared with the pneumatic braking,the segmented electro-pneumatic braking system has the greatest strength in braking capacity for C64 k train and the marshalling 2+0 train,and the minimum for C80 train and the marshalling1+1 back train.At the same time,on flat line after adopting electro-pneumatic braking,the braking capacity of all kinds of marshalling trains is slightly strengthened under small reduction braking and emergency braking conditions,the train braking distance can be shortened by about 13.7%-49.6% under the common braking and large reduction conditions,indicating that the segmented electro-pneumatic braking can strengthen the braking capacity of trains under various marshalling conditions.From the comparison of the coupler force on flat line,the improvement extent of the segmented electro-pneumatic braking system is the minimum for the C64 k train and the marshalling 1+1 back train,and the greatest for the C80 train and the marshalling 1+1 combination trains.At the same time,when braking under small pressure reduction,the coupler force under two braking modes is at a low level and have minor difference.Under the common braking condition of large pressure reduction,the reduction effect of the coupler force is relatively significant,and the overall reduction degree is about 10.5%-68%.Under emergency braking,the maximum reduction can be about 52.2%.From the tensile coupler force after the releasing of the cyclic braking on the long and steep ramps,the reduction of the maximum tensile coupler force of all kinds of marshalling trains after the installation of the electric control device is more than 21%,especially for the 20000 t marshalling 1+1 train running at present,the reduction degree of the tensile coupler force is as high as 68.7%,It shows that the segmented electro-pneumatic braking can effectively reduce the tensile coupler force caused by the releasing of cyclic braking on the long and steep rampways.