Study On Mechanism And Analysis Theory Of Train Derailment

Train derailment, which occurs frequently in China and other countries of the world, will lead to interruption of train operation, tuming-over of the train and even heavy casualties. Research of train derailment has been an important subject in railway transportation all over the world. The research on the safety of railway transportation is listed as an important domain and priority subject in the "Medium and Long Term Plan Compendium of Development of Science and Technology of China (2006-2020)." Since the launch of the speed-up campaign in the Chinese railways, freight train derailment accidents have been on the rise and have reached 70% of all grave and serious accidents in train operation. With the widely-developed construction of the high speed railway line for passenger traffic, to guarantee the safety of train operation is much more important than before. The problem of train derailment has been studied for as long as more than one century and a great number of achievements have been made, however, the mechanism of train derailment has not been understood fully and there still exist three fundamental problems in the analysis theory of train derailment. Therefore, there is a pressing need to make clear the train derailment mechanism, solve the three fundamental problems and propose a new theory about train derailment analysis, which will be of great theory value and economic and social benefits. The main contributions of the dissertation are as follows.1. The three fundamental problems existing in the derailment studies are profoundly summarized based on largely analyzing the research status about train derailment in China and other countries of the world. The methods for solving these problems are also introduced.2. The train derailment mechanism, which is the result of losing stability in lateral vibration status of train-track (bridge) time-varying system (hereinafter referred to as the System), is proposed for the first time.3. The conditions for losing stability in the lateral vibration of the System and causing train derailment is that the work done by the limited resisting forceσ_c equals the maximum input energyσ_p,max. And the condition for the stability of the lateral vibration of the System and no derailment of the train is thatσ_c＞σ_p,max.4. A set of new theories for random energy analysis of train derailment is proposed. And the main contents are as below,(1) Taking into account the connecting conditions of wheel-rail displacement and the influence of the clearance between wheel flange and gauge line, the matrix equation of the spatial vibration of the System is established to calculate the whole course of train derailment.(2) The geometric criterion of train derailment is established.(3) The method for calculating the whole course of train derailment is put forward.(4) The vibration responses of the whole course of train derailment and the relationship curve between the work done by the limited resisting force of the lateral vibration of the Systemσ_c and train speed V is calculated out for the first time. And the expression of the increment△σ_c of theσ_c is obtained.(5) The method for calculating the increment△σ_p,max of the maximum input energy of the lateral vibration of the Systemσ_p,max is put forward.(6) The energy increment criteria for determining the stability status of the lateral vibration of the System and train derailment is established.(7) The preventive measures against derailment and methods for stipulating preventive standard against derailment are proposed.5. To counter train derailment under abnormal condition of train operation, a derailment warning device is invented to hold back the derailment accident and a national patent (No. ZL 2004 2 0068176.2) is also gained. To counter train derailment under normal condition of train operation, i.e. undefined derailment, the technical principle for a preventing derailment warning system is proposed, which provides a theoretical basis for the warning system.6. The bogie frame hunting wave of a freight train on Beijing-tonghua railway line is measured. And the relationship curve between the standard deviationσ_p, of the bogie frame hunting wave of the empty car and train speed V is obtained for the first time, which is the practical basis for analyzing the freight train derailment. The bogie frame hunting wave of a high speed train on Qinhuangdao-shenyang railway line for passenger traffic is measured. And the relationship curve between the standard deviationσ_p of the bogie frame hunting wave of the high speed train and train speed V is obtained for the first time, which lays a practical foundation for analyzing the high speed train derailment.7. A set of software for analyzing train derailment with property right is independently developed based on the theory of random energy analysis for train derailment. Calculations are firstly made for 21 vibration cases of train-track (bridge) time-varying system, nine of which are derailed, while twelve not. The calculated results coincide with the practical situation. This has demonstrated that the problem of train derailment analysis that has not been solved for almost one hundred years has been broken through.8. A grave derailment accident of number 33117 freight train on Changchun-tumen railway line is analyzed. The loss of the lateral stability of the train-track time-varying system is regarded as the cause of the train derailment. This conclusion has been applied by the Safety Supervision Department of the Railway Ministry of China.9. Safety analyses are made of trains running on six bridges such as Nanjing Yangtz river bridge etc. with their lateral vibration amplitudes exceeding specifications. The calculated results are that trains on these bridges will not derail within design speeds, which are in agreement with the practical facts. These results have been accepted and applied by Shanghai, Shenyang and Zhengzhou Railway Administration Bureaus etc., respectively. The strengthening or changing of beams on these bridges has been avoided, which yielding direct economical benefits 84million yuan. All of these proves that the problem has been solved of safety analysis of trains running on bridges with their lateral vibration amplitudes exceeding specifications.10. The necessity of derailment controlling analysis of trains on bridges is demonstrated. Derailment controlling of high speed trains running on supper major bridges such as Tianxinzhou combined highway and railway bridge, Hujiawan bridge and Hengyang-xiangjiang bridge etc. on Wuhan-guangzhou railway line for passenger traffic is analyzed. The calculated results provides an important theoretical basis for the design of these bridges, which have been accepted and applied by China Zhongtie Major Bridge Engineering Group Co. Ltd and the Fourth Survey & Design Institute of China Railways.