Situational Adaptation of the Open Wagon Body to Container Transportation
, Alyona Lovska 1,*, Glib Vatulia 2, Mykhailo Pavliuchenkov 3, Oleksandr Kravchenko 1 and Sebástian Solčanský 1Round 1
Reviewer 1 Report
In this article, the possibility of carrying containers in open wagons by considering possible movements of containers and allowable stress is surveyed.
1- It is better to demonstrate how equation 1 is obtained.
2- Some system parameters are not introduced in the manuscript. Authors are suggested to define all variables after the first appearance in the paper. The physical and geometrical quantities of the system are chosen from which reference?
3- The manuscript contains two Figure 2. The authors should explain how to acquire the Accelerations on the open wagon in Figure 2. In what software Figure 6 is obtained? The explanation about the utilized software is not sufficient.
4- In the conclusion, the authors should describe a summary of the manuscript.
5- The discussion is not informative and is very briefly organized. The authors should add more novel results to the article, especially in the discussion section.
6- What are the assumptions of the proposed model?
7- The authors should add more clarification about the novelties and differences between the present article and available investigations in the technical literature in the last paragraph of the introduction section. The literature review in the introduction section is not comprehensive, especially in the field of transportation and traffic management. It is recommended that the following articles be explained in detail: DOI: 10.1061/(ASCE)ME.1943-5479.0001015. DOI: 10.1109/TITS.2022.3182410. DOI: 10.1109/TITS.2023.3269794.
8- What are the limitations and privileges of the proposed model and solution technique used in this paper?
9- The English written language of the article should be improved.
The English written language of the article should be improved.
Author Response
Dear Reviewer!
The team of authors would like to thank you for your interest in our work and for your comments, which certainly improved this article.
Regarding your comments, we would like to respond as follows.
- It is better to demonstrate how equation 1 is obtained.
We have tried to make appropriate explanations and have also provided a reference to a literature source which gives detailed information regarding this model.
All corrections in the text of the article have been highlighted in green.
- Some system parameters are not introduced in the manuscript. Authors are suggested to define all variables after the first appearance in the paper. The physical and geometrical quantities of the system are chosen from which reference?
We have explained the missing parameters in the text of the article. We have also provided information on what considerations are used to select the physical and geometric parameters of the system.
In determining the input parameters of the mathematical model, the physical and geometrical parameters of the open car model 12-295, which has been considered as a prototype, as well as the container of size 1CC were taken into account.
Body mass of open car body is accepted equal to 14.6 t, moment of inertia – 308 t∙m2, wagon base – 8.65 m. Bogie spring suspension stiffness is 8000 kN/m and coefficient of relative friction is 0.1.
For the container – mass is 24 t and moment of inertia is 220.3 t∙m2. The height of the container is 2.35 m.
- The manuscript contains two Figure 2. The authors should explain how to acquire the Accelerations on the open wagon in Figure 2. In what software Figure 6 is obtained? The explanation about the utilized software is not sufficient.
Thank you for your comment. We have corrected the numbering of the figures accordingly. We have also explained how the accelerations shown in Figure 3 were obtained: the mathematical model (1) was reduced to the Cauchy normal form, and after that its integration with a fixed step was carried out. For this purpose, the classical algorithm for solving equations presented in [26] was used. The calculations were performed in the software package MathCad.
- In the conclusion, the authors should describe a summary of the manuscript.
Thank you for the good point. We have made a discussion section at the end of the article.
- The discussion is not informative and is very briefly organized. The authors should add more novel results to the article, especially in the discussion section.
We have tried to take this point into account and have included relevant information at the end of the article.
- What are the assumptions of the proposed model?
We have given in the text of the article the relevant limitations and assumptions made when modelling the loading of an open car. Due to the fact that there are many of them, we have not indicated them in the letter to the respected Reviewer. They are highlighted in green in the text of the article.
- The authors should add more clarification about the novelties and differences between the present article and available investigations in the technical literature in the last paragraph of the introduction section. The literature review in the introduction section is not comprehensive, especially in the field of transportation and traffic management. It is recommended that the following articles be explained in detail: DOI: 10.1061/(ASCE)ME.1943-5479.0001015. DOI: 10.1109/TITS.2022.3182410. DOI: 10.1109/TITS.2023.3269794.
We have analysed these publications and referenced them in the paper.
- What are the limitations and privileges of the proposed model and solution technique used in this paper?
The advantage of this study is that the authors adapt the well-known mathematical model of flatcar dynamics to determine the dynamics of a container laden open car. Previously, no attention has been paid to the dynamics and strength study of container laden open cars. At the same time we considered one of the most unfavorable loading conditions of open car - "stretching - jerk". This is because this mode is subject to the greatest amount of longitudinal load in operation.
In further research we will consider the movement of a open car as part of a train, and we plan to conduct a corresponding experiment.
- The English written language of the article should be improved.
We have tried to take this observation into account.
We hope we have understood your comments correctly and have taken them into account.
Please view the article again.
Best Regard,
Authors
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The paper deals with actual topic utilization of old stock open freight wagon fleet for container transportation. The design of adapter frame is proposed in the paper. Such frame is capable to be put into the open wagon and provide standard points for a container fixing.
More than scientific novelty the paper shows the amount of engineering work that has been done. The paper focuses on the results of FEA calculations.
The paper would benefit from several improvements. Therefore, a major revision is suggested. In the revised paper, please address the points below.
General:
Instead of using of very similar figures (for example Fig. 4 and 19), clearly specify the boundary conditions of each FEA calculations case. I.e., the values of loading forces and their distribution on the structure, the motion constrains and the reaction forces placement.
Please clearly specify how is the container fixed to the wagon structure or the container module and how is the module fixed to the wagon structure. Please explain how are such connections represented in your FEA model. Please also comment on the very high accelerations up to 4g (assuming vertical although this is not entirely clear from the text) and the assumption of the transmission of the longitudinal forces between the container and the wagon by friction.
Please explain if and how is the container’s own structural stiffness implemented in your model.
Please make some correlation of the loading forces applied to your FEA model with the requirements of international standards.
Please reference each figure from the text of the paper.
Page 5, Line 174
Please, could you be more specific on the calculation conditions? Especially track irregularities, vehicle speed, friction coefficient, etc.
The paper is not very clearly written and understandable, it would benefit from careful check of English and the check of the correlation of authors ideas and the text of the paper.
Author Response
Dear Reviewer!
The team of authors would like to thank you for your interest in our work and for your comments, which have certainly improved this article.
Regarding your comments we would like to note the following.
- Instead of using of very similar figures (for example Fig. 4 and 19), clearly specify the boundary conditions of each FEA calculations case. I.e., the values of loading forces and their distribution on the structure, the motion constrains and the reaction forces placement.
Thank you for your comment. We have made the relevant information in the text of the article. All corrections have been highlighted in green.
- Please clearly specify how is the container fixed to the wagon structure or the container module and how is the module fixed to the wagon structure.
The demountable module is attached in the open car via fittings that are located in its corner parts. And fitting stops are installed in the open car, the same as on flat cars. The fittings are inserted into the fitting stops and the module is thus secured in the body of the open wagon.
The container itself is attached to the module in the same way as for flat wagons - through the fittings placed in its corner parts. At the same time, fittings are placed on top of the module (shown in Figure 8). We have entered this information in the text of the article.
- Please explain how are such connections represented in your FEA model.
We have outlined the issues of the links between the module and the body and the module and the container in the article.
The calculation diagram shown in Fig. 5
It was taken into account that the container was not fastened to the body, but rested on the floor. It meant that the option when the container was not fastened to the body was also included.
The body was fastened at the horizontal surfaces of the centre plates, which modelled the interaction of the body with the bogie.
Calculation diagram in Fig. 16.
The module was secured at the corner fittings. Here the rigid fixing was used. Such securing was justified by the fact that the cantilever part of the module rested on the end wall of the open wagon, which compensated for the module’s own degree of freedom in the longitudinal plane.
Calculation diagram on fig. 20.
The body was fastened at the horizontal surfaces of the centre plates.
- Please also comment on the very high accelerations up to 4g (assuming vertical although this is not entirely clear from the text) and the assumption of the transmission of the longitudinal forces between the container and the wagon by friction.
The resulting acceleration value can be explained by the fact that the container was not fastened in the body and had its own degree of freedom. This acceleration value is consistent with that presented in the research by Prof. Bogomaz [16]. However, it concerned the longitudinal dynamics of the flat wagon loaded with tank containers. Besides, his calculation included the own displacements of the tank containers due to the gaps between the fittings and the fitting stops.
- Please explain if and how is the container’s own structural stiffness implemented in your model.
The loading of the container itself has not been considered at this stage. We have only investigated the body of the open car. But we will certainly pay attention to this issue in future works. Thank you!
- Please make some correlation of the loading forces applied to your FEA model with the requirements of international standards.
Thank you for your comment. At the moment, the body calculation is done according to the standards that take place for 1520mm gauge cars.
There is an international standard, which is indicated in the list of references under the number [18], however, it contains other values of longitudinal loads, because it is mainly used for 1435 mm gauge cars. After the completion of this study, we plan to consider the issues of the dynamics and strength of the car, taking into account the loads laid down in this standard.
- Please reference each figure from the text of the paper.
Thank you! We have taken this comment into account.
Page 5, Line 174
Please, could you be more specific on the calculation conditions? Especially track irregularities, vehicle speed, friction coefficient, etc.
In the text of the article, we have made the relevant information available. Regarding wagon speed and track unevenness, we would like to note that these issues will be considered for the case of a wagon in a train (III mode). At this stage of research, we considered the І mode, it corresponds to the most unfavorable case of loading a car. In this case we took into consideration the scheme "jerk - stretching", because in this case the maximum value of longitudinal load on the open car body applies.
The movement of the car as part of the train will definitely be considered at the next stage of the study.
We also improved English.
We hope we have understood your comments correctly and have taken them into account.
Please view the article again.
Best Regards,
Authors
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
All the essential amendments have been made. The manuscript is acceptable and can be posted in the journal.
Author Response
Thank you!
