Purpose. The main design requirements of the modernized cars are those allowing reduction of operating costs and improvement of economic efficiency of their use. Due to the relevance of this subject the work presents the complex of conducted research, which will allow in prospect to use the universal flatcar, converted according to the Technical specifications TU 3182-065-71390252-2911 for container service. The research includes: evaluation of strength, fatigue safety of the design elements and conformity assessment of the strength characteristics of the modernized flatcar elements to the regulatory documents. Methodology. The analysis covers the use of specialized and universal rolling stock for transportation of containers, as well as the issues of modernization of universal cars. The strength of the flatcar bearing structure is evaluated based on the complex of numerical and experimental studies. The experimental part includes the static, repair load and impact tests. The car strength qualities and the fatigue safety are evaluated on the basis of calculated and experimental data. Findings. The conducted static, repair load and impact tests, given the quasi-static longitudinal forces, allowed the evaluation of the car structure strength according to the regulatory documents. The calculated and experimental data make it possible to assess the fatigue safety of structural elements. The present work is completed by obtaining the results that allow performing reasonable re-equipment of universal flatcars with baseplates with fitting stops to fasten the containers. Originality. The results of calculated and experimental studies showed that the modernized flatcars meet the conditions of strength and have sufficient fatigue safety factor. This makes it possible to recommend the re-equipment of universal flatcars for all car-repair enterprises that submitted the prototypes. Practical value. The complex of works was conducted that demonstrated the possibility of re-equipment of universal flatcars for the transportation of large containers. Part of the car fleet, kept in reserve, with little material costs can be transferred to the operational fleet. The modernization -re-equipment of universal flatcars with stationary specialized devices will increase the car usability coefficient.

Purpose. To determine the effect of the force components acting in the axle box and the central spring suspension on the stresses occurring in the side frame of the three-piece bogie. Methodology. To assess the effect of the forces acting on the side frame on the stresses in it, we developed a finite element model of the side frame. After that, we carried out an assessment of its stress-strain state under loading conditions corresponding to the І and ІІІ design modes. According to the results obtained, we determined the stress concentration points in the construction, which are selected as check ones for further studies. Also, as checkpoints we took the points corresponding to the sensor locations when estimating the stresses in the side frame during the tests. At the next stage, we applied unit loads in sequence at the interaction points of the side frame with the boxes and the central spring group. To obtain a more accurate result, the unit forces were balanced by the corresponding forces and moments of inertia. With each loading variant, tensors of stresses arising from the action of unit loads were obtained at checkpoints. On the basis of the stress tensors obtained, we determined the corresponding equivalent stressesthe sensitivity coefficients. Findings. The paper determines the stress sensitivity coefficients in the three-piece bogie side frame to external loads acting on the side frame from the side of axle box and central spring group. Based on the results of the assessment of the coefficients obtained, we determined the forces having the greatest influence on individual sections of the side frame. We estimated the possibility of using the obtained results in optimizing the parameters of the bogie spring suspension to increase the strength and durability of the side frame. Originality. For the first time, the effect of individual components of the forces acting on the side frame on the stresses in it has been estimated. Practical value. The obtained result can be used in the design and optimization of three-piece bogies, to improve the side frame durability. The stress tensors obtained can be used to estimate the effect of complex loading on the side frame strength and durability.

THREE-ELEMENT BOGIE SIDE FRAME STRENGTHPurpose. To evaluate the effect of different loads on the stress-strain state of the freight car bogie side frame, as well as to evaluate the distribution of the stress fields in the design of the freight car bogie side frame supported through the horizontal surface and through the horizontal and inclined surfaces of the pedestal opening. Methodology. A volumetric finite element model of the side frame of ZK-1 bogie of the freight car was designed. The forces under the current regulatory documentation for theoretical research were applied to the model, the stress arising in the model elements were determined. The static tests of ZK-1 bogie side frame were conducted; they allowed determining the stresses in the key points of the frame under the action of forces in accordance with the existing procedure of static tests of the freight car bogie side frame. To check the quality of the finite element model we determined the stress in the model under the action of forces corresponding to the static requirements. The corresponding coefficients were determined to match the stress obtained through theoretical studies and static tests. The results of theoretical and experimental studies of stress for dangerous sections of the side frame design were compared. Findings. The regulatory documentation for carrying out experimental research of the side frame strength does not fully take into account the load acting on the frame during its operation and that provided while assessing the side frame strength theoretically. The strength evaluation of the side frame by the results of field tests only does not give a complete picture of the distribution of stress fields, as the provided sensor installation points do not cover most of the design elements with possible stress concentration. Originality. The loads applied to the side frame during theoretical and experimental studies were compared to the loads acting during operation. The impact of use of inclined surfaces in the pedestal box opening was evaluated. Practical value. The obtained results allow the more accurate assessment of the three-piece bogie side frame strength, as well as allow you to choose the more preferred method of side frame support in the axle box.

An important role in the market of transport services belongs to container transportation. Railroads, especially under the conditions of increased competition from road transport, must respond quickly to the needs of the market and the growing demand for container transportation, including interstate traffic. Demand for container transportation can vary significantly during the year, which testifies to the expediency of introducing removable equipment on universal railroad freight cars that are involved in the deliveries of containers. This paper reports the design of a removable frame structure for a universal platform that could carry two 20-ft or one 40-ft container. The proposed technical solution does not require changes in the structure of the car and changes in its model; with a decrease in the demand for container transportation, it would allow this car to be used for its main purpose. According to the current methodology, the efforts that operate on the frame during the transportation of containers have been determined. The strength of the proposed structure was estimated by a finite-element method. The maximum stresses arising in the proposed structure are 164.4 MPa; they occur in the corners of the stops attached to the stand-up staples of the platform. The resulting stress values do not exceed the allowable ones. The results of calculating the removable equipment indicate its sufficient strength. Requirements for placing cargo on the rolling stock assume a mandatory check to fit the dimensions, which confirmed that the container hosted by the frame does fit them. The proposed structure makes it possible to abandon disposable fastening parts, improve the safety of container transportation, and increase competitiveness in the container transportation market.

The goal of the article is to evaluate the possibility of improving the design of an open wagon body in order to improve traffic safety when transporting cargoes whose height is beyond the upper belt of the side wall (cargo loading with a “hat”). To achieve it, the authors have proposed a variant of a pull-out bar in a wall rack. In lazy state such bars located inside racks, but during transportation of timber, pipes etc they are pulled out above the wall upper belt to prevent cargo from rolling out. These bars are quite light (mass of one pull-out bar is equal to 3 kg, that corresponds to 36 kg of an additional equipment per a wagon), but they considerably facilitate fixing cargo in an open wagon replacing additional wooden fixing racks. It also makes the transportation more reliable due to elimitation the possibility of skew and jamming of fixing equipment. Strength of the proposed element and the entire wagon side wall is estimated with the finite element method. The proposed bars withstand normative loads, and holes in the upper belt for them do not lead to desrease of the wall carrying capacity.