# Experimental Studies on the Strength of a Flatar during Shunting Impacts
## 2 Analysis of Recent Studies and Publications  
The strength indicators of the model T11 tank container placed on the flatcar during a shunting collision were determined by [PERSON] and [PERSON] [4]. The results of the theoretical studies were confirmed by experiments conducted using the method of electrical strain gauging. The authors identified the most loaded structural areas and explained why the stresses were concentrated in those areas. However, they considered only the load of the tank container and did not investigate the strength of the flatcar. The impact load of the vehicle was determined by [PERSON] and [PERSON] [5]. The authors used the acceleration as an experimental variable and a component of the dynamic load. The calculation was carried by means of mathematical modelling. The second-order differential equations were solved using the Lagrange method. A unified concept of impact strength to optimize the body the rolling stock unit was considered by [PERSON] and [PERSON] [6]. It was represented as a rigid frame structure. The optimization problem was reduced to minimizing the body weight, taking into account the stress restrictions. The calculation was carried out with the finite element method, and the results obtained confirmed the feasibility of the proposed structural solutions. However, in the papers under consideration, the authors made only the theoretical determination of the strength of vehicles though using modern engineering software. The dynamics of the rolling stock using an experimental laboratory car moving along complex track sections were investigated by [PERSON] and [PERSON] [7]. The car had special equipment for recording the main dynamic indicators. Some measures for safe operation of rolling stock were proposed. The influence of track irregularities on the dynamic indicators of rolling stock was investigated. The effects of longitudinal forces acting on the load-bearing structure under operating conditions were also taken into consideration. The peculiarities of the running strength and dynamic tests of the flatcar model 13-9975 were described by [PERSON] et al. [8]. It was taken into account that the flatcar was loaded with 20- and 40-foot containers. The authors determined the dynamic indicators of the flatcar under the main operating load conditions and took into account mainly the loads acting on the flatcar being part of the train. It is important to note that these studies do not present the results of determining the strength of the bearing structure of the rail car under a shunting collision, though it causes the highest load on the bearing structure in operation. The study of the fatigue strength of the open wagon body was carried out by [PERSON] et al. [9] and [PERSON] et al. [10]. The open wagon model C80B, built in China, was chosen as a prototype. The calculation was carried out using the finite element method. The assumptions and limitations of this calculation are given. The results of the study demonstrated that the method of predicting the fatigue strength of the body based on dynamic modelling is possible. At the same time, this study did not include the case of a shunting collision of the car in operation. The strength calculation of the wagon was carried out by [PERSON] [11]. The author considered only main design forces acting on the wagon operating on mainline tracks. Numerical values of these forces were selected according to the normative technical documentation. The accepted design diagram of the wagon body was substantiated. Moreover, the publication gives the analysis of the results obtained. It is important to say that the authorsof [10; 11] did not conduct experimental research of the strength of the wagon body. This would make it possible to verify the results obtained theoretically. [PERSON] et al. [12] calculated the loading of the flatcar with containers including the elastic-friction interaction between container fittings and fixed fittings.