## 2 Methods and the Data
The centrifugal force on the ferry (Figure 7), and thus, on the rail cars located on it, was defined by the following formula [24]:  
\[C=\frac{D\cdot\vartheta^{2}}{R}, \tag{6}\]  
where \(D\) is the ship displacement of the train ferry; \(R\) is the turning radius; and \(\vartheta\) is the turning speed. As is known from theoretical mechanics, the centrifugal force can be found using this formula:  
\[C=D\cdot\omega^{2}\cdot\rho, \tag{7}\]  
where \(\omega\) is the angular speed and \(\rho\) is the turning pole. When the ferry turned around two stern screws and one front screw began to work, the stern screws acted in opposite directions and formed the moment that facilitated the turning motion of the ferry. The centrifugal force and the forces through the chain binders acted on the rail cars located on the ferry decks. A diagram of the forces acting on the car body through the chain binders when the ferry turned around is given in Figure 8.  
Figure 8: Diagram of the forces acting on a car body through the chain binders when the ferry turns. 1—rail track; 2—car; 3—ferry deck; 4—chain binder; \(F_{x}\) and \(F_{y}\)—projections of the forces acting on the car body through the chain binder. Figure 7: Diagram of the centrifugal force on the ferry with a car on board when the ferry turns. 1—train ferry; 2—stem engines; 3—rail car; 4—stem engine. The approximate speed of the turn of the train ferry was \(\vartheta=1.3\) km/h = 0.36 m/s. For the farthest car body from the sternpost, \(R=79\) m.  
Thus, considering that \(D=23744\) tons, the value of the centrifugal force was \(C=39\) kN. The force transferred to the car body through the chain binder was \(F=C/a\). Therefore, the force components in the longitudinal and transverse directions were defined as:  
\[F_{x}=F\cdot\cos\beta,F_{y}=F\cdot\sin\beta. \tag{8}\]  
The values of the components of the centrifugal force obtained were \(F_{x}=4.9\) kN and \(F_{y}=8.4\) kN. The loads obtained were included in the strength calculation for the bearing structure of an open car with honeycomb panels in the body bolster. It was considered that the car was secured on the deck with the fixing units located on the body bolster (Figure 9) [24]. The unit consisted of the bottom part of the body with hook guide 1 (Figure 9a), which was completely identical to the hitch geometry of the chain binder and intended for interaction with the fixation unit, radial lug 2 for reducing the load in the contact area between the fixation unit and the support part, cylindrical part 3 supporting the contact between the hook and the fixation unit, and the upper part of the body with prismatic part 4 connecting the working and additional parts of the unit with technological reinforcement 5. Support parts 6 were intended for securing the unit on the bolster beam of a rail car (Figure 9b). In this study, the material of the honeycomb panels and the sizes of their cells were considered conceptually. In the course of the mathematical modelling of the load on the bearing structure of the car, the parameters of the viscosity and stiffness of the panels were determined, which can later be used for selecting a material with appropriate parameters and characteristics. The strength calculation was made with the finite element method in SolidWorks Simulation version 2015 (CosmosWorks) [27; 28; 29; 30]. The authors adhered to the following algorithm while investigating the strength of the body:  
1. Building the finite element model of the open car body;
2. Developing its calculation scheme;
3. Developing the body-fixing scheme;
4. Selecting the construction material;
5. Carrying out strength calculations, in which the [PERSON] criterion was used (the fourth theory of strength). It was taken as the calculation criterion because the material of the body structure was isotropic. The main hypothesis of this calculation was that a lower dynamic load of the body could improve the strength indicators.