## 5 Conclusions  
1. This study presents an improvement of the bearing structure of an open car in order to provide safe transportation via train ferries. It includes the application of elastic, viscous honeycomb panels between the vertical sheets of the intermediate, end, and body bolster beams; the intermediate beams of the open car frame are made of a boxed section. This solution may reduce the load on the bearing structure of an open car transported via sea. The higher efficiency of a honeycomb panel can be achieved at a viscous resistance coefficient in the range of 150-165 kN s/m and a stiffness in the range of 500-520 kN/m.
2. This study also includes a determination of the bearing structure of an open car during rolling motions. As calculated, the use of honeycomb panels can decrease the dynamic load by about 25% more in comparison to that of a standard structure. The maximum acceleration for the bearing structure of an open car with the standard frame was 0.38, and that for the improved structure was 0.29 m/s\({}^{2}\).
3. The authors determined the load of the bearing structure of an open car during the turning motion of a train ferry; it was found that, with a turning speed of the train ferry of \(v=0.36\) m/s and a turning radius of \(R=79\), the value of the centrifugal force was \(C=39\) kN. The components of the centrifugal force acting on the bearing structure of an open car through the chain binders were \(Fx=4.9\) kN and \(Fy=8.4\) kN.
4. The strength of the bearing structure of an open car transported via a train ferry was studied. The strength of the bearing structure of an open car transported via sea was calculated.
5. The results of the calculation made it possible to conclude that the maximum equivalent stresses were in the bolster beam; their value was about 240 MPa, which was 30% lower than the loads in the standard bolster beam. The maximum displacements in the bearing structure of an open car were in the middle part of the centre still; they were about 5 mm.
6. The results of the strength calculation for the bearing structure of an open car during the turning motion of a train ferry demonstrated that the maximum equivalent stress was about 185 MPa, and the displacements were about 5 mm. Thus, the strength of the bearing structure of an open car has been provided.  
Conceptualization, J.G. and A.L.; methodology, A.L.; software, J.D. and O.F.; validation, A.L., J.D. and M.B.; formal analysis, A.L.; investigation, J.G.; resources, O.F.; data curation, A.L. and O.F.; writing--original draft preparation, M.B. and J.D.; writing--review and editing, A.L. and J.G.; visualization, A.L.; supervision, J.D.; project administration, A.L.; funding acquisition, A.L. All authors have read and agreed to the published version of the manuscript.  
This publication was supported by the Cultural and Educational Grant Agency of the Ministry of Education of the Slovak Republic under the project \"Implementation of modern methods of computer and experimental analysis of properties of vehicle components in the education of future vehicle designers\" (project No. KEGA 036 ZU-4/2021). This research was also supported by the Slovak Research and Development Agency of the Ministry of Education, Science, Research and Sport of the Slovak Republic in the Educational Grant Agency of the Ministry of Education of the Slovak Republic under the project VEGA 1/0513/22 \"Investigation of the properties of railway brake components in simulated operating conditions on a flywheel brake stand. This publication is funded through the Recovery and Resilience Plan for Slovakia under the project No. 09I03-03-V01-XXXXX\" and project \"Scholarships for Excellent Researchers Threatened by the Military Conflict in Ukraine\", which has the code 09I03-03-V01 too.  
Not applicable.  
The authors declare no conflict of interest.