Study On Fundamental Theory And Application Of Overweight Goods Safety Transportation In Railway

Overweight goods, such as some large equipment of electric power industry, mechanical industry and chemical industry, are mostly important equipment in national construction. They are not only large, heavy and complex in structure, but also expensive and play an important role in the development of national economy. They must be transported safely and timely.However, the concept of overweight goods has not been used for long in our country’s railway freight transportation, and not until2007, it occurred in some related freight rule for the first time. However, the rule merely gives a simple definition to the concept and classification of overweight goods which is too ideal and deviates from reality. Meanwhile, we lack some research about overweight freight transportation, the present research is merely a qualitative description for current phenomenon. Since there exists no corresponding theoretical system and no perfect rules, the overweight goods can’t be understood properly in the daily work, which leads to the lack of criterion according to transport organization and the passiveness and mistake in work. Thus, we must study and discuss deeply about the basic theory of the safety of overweight goods transportation and develop a set of integrated theory system which is essential for us to guide the overweight goods transportation work.Based on the theories and methods of structural mechanics, vehicle engineering, bridge engineering, finite element calculation, railway freight technique and etc., the thesis gives a deeper study about the fundamental theory and application of overweight goods transportation. At the same time, this paper verifies its result with test data and related cases.The main findings and conclusions are shown as follows:(1) The connotation and characteristics of overweight goods are analyzed and a new definition is proposed. On the basis of related conception about different transportation ways at domestic and abroad, the thesis analyzes the connotation of overweight goods, and then renews the definition, indicates the characteristics of the overweight goods, deduces the reasons of becoming overweight. Besides, several related conceptions are defined involving overweight goods transportation. Then, the overweight goods are compared and analyzed with several other goods to avoid being confused. The new definition to the overweight goods given by this thesis can reflect its influence to the railway infrastructure comprehensively and can reflect its demanding to the transport organization, which overcome the weakness of the original definition.(2) The thesis discusses the factors that influence the overweight goods transportation, analyzes the influence of each factor towards the overweight goods, and draws the conclusion:the main factor include freight, vehicles, bridges, lines, construction clearance, loading and securing plan, etc. Those factors affect the transportation safety, organization difficulty, operating conditions, freight charges and transportation infrastructure safety of overweight goods. We must consider those factors synthetically when organizing transportation. The analyses in this part give a light for the future work and also, it is the necessities for later research.(3) The thesis studies the function mechanism of heavy duty freight cars to the bridges and lines. By selecting the typical bridges and routs, taking D2car as an example, this thesis establishes the finite element calculation model of track and bridge separately, calculates the stress and deformation of track structure and bridge under several parameters and then, these are compared between heavy duty freight cars and several common locomotives. At the same time, combining operating trials and proper rules and also taking the relationship of dynamic and static loads into consideration, the finite element calculation result are checked. The results indicate:generally, compared with the common locomotives, the heavy duty freight cars have larger load to the lines and bridges and can even destroy them.(4) The classification grade and its judging methods about overweight goods are proposed. For the problems existing in the classification of overweight goods, the thesis makes a theoretical analysis and deduction of the applied load acted on the bridge when the center of gravity of overweight freight car has some offset. With that, it defines the concept and gives the calculation formula of the eccentric coefficient, and then, redefines general formula for the coefficient of live load. Furthermore, the thesis puts forward the methods of the classification grade and judgment to the overweight goods. Finally, through a case, the thesis proves the new methods is reasonable. Above all, the new methods not only consider the bridges that adhere to the design standards, but also take the bridges that with not enough carrying capacity into account. Compared with existing methods, the new one can reflect the overweight level more factually since it considers the condition of loaded car’s eccentricity and bridges.(5) The ideology is proposed that the measures on the safety of overweight goods transportation should start from improving the transportation scheme of overweight goods, and optimization ways of it are also advanced. On the basis of the main components of the transportation scheme of overweight goods, aiming at decreasing the influence of overweight goods to the bridges and tracks, the thesis gives some related requirements about the transportation scheme of overweight goods, and proposes the proper optimizing formula from several aspects, including the selection of vehicles, the load pattern design, the marshalling of vehicles, the curve velocity and the vehicle speed of passing bridge. Finally, through a case, the thesis analyzes the effect of overweight goods under different transportation schemes.The thesis analyzes and discusses about the basic theory and application problem of the overweight goods transportation systematically for the first time from the aspect of transport organization, and builds the basic theoretical frame for the safety of overweight goods transportation. The research results and conclusions will provide the basis for perfecting rules, improving the level of transport organization and management.