Effects of Particle Size and Grading on the Breakage of Railway Ballast: Laboratory Testing and Numerical Modeling
Round 1
Reviewer 1 Report
Comments and Suggestions for Authors
This study examines the splitting behavior of ballast grain with varying particle sizes under diametrical compression. The article offers a scientific account of the experimental methodology employed to evaluate the tensile strength of railway ballast. The approach seems good. However, a major correction is suggested.
1. The introduction section, including literature review is not strong and need to be improved and supported by references.
2. The article flow should be improved and re-arranged properly.
3. Conclusion section can be more condensed and concise.
4. Row 405, please correct the mistake in the word “shearin”
5. To ensure the credibility of the findings, it is essential to disclose details regarding the quantity of samples tested and their representativeness concerning real-world ballast materials.
6. While the paragraph offers a synopsis of the findings, it lacks specific numerical data, p-values, or information about the statistical tests employed to substantiate the assertions made. Including these elements is imperative to uphold scientific rigor and the potential for reproducibility.
7. The study should delve into the relevance of its findings in the context of actual railway ballast applications. Factors like variances in ballast materials, environmental variables, and varying load conditions should be addressed to gauge the applicability of the research in practical engineering scenarios.
8. If numerical DEM modeling was utilized, it is crucial to elaborate on the model's fidelity to real-world observations. Validation against physical test outcomes or field data is critical to verify the accuracy of the simulations.
9. The article overlooks any mention of limitations or uncertainties linked to the research. Recognizing these aspects is vital for transparency and aids readers in comprehending the study's scope and potential constraints.
10. In addition to presenting valuable insights into ballast's mechanical behavior, How can the results be advantageous to the railway industry?
11. Expanding on practical implications and proposing avenues for future research can further enrich the field of railway engineering.
Comments on the Quality of English LanguageModerate editing of English language required
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe article "Effects of particle size and grading on the breakage of railway ballast: laboratory testing and numerical modeling" deals with an important and current topic of railway engineering. The authors investigate how the particle size and grading of ballast affect its breakage under cyclic loading. They use both laboratory tests and numerical simulations to study this problem.
The article is well-written and organized, and the results are clearly presented and discussed. The combination of numerical and laboratory methods is interesting and innovative, as it allows to capture the complex behavior of ballast under different loading conditions.
However, I have some comments and suggestions that could improve the quality of the article:
- The authors do not explain sufficiently what motivated them to choose either laboratory or numerical methods for each case. In my opinion, it would be reasonable to conduct both laboratory and numerical tests for each case, and compare the results. This would provide more validation and reliability for the numerical models, and more insight into the physical mechanisms of ballast breakage.
- I have some doubts about the connections between the points in Figure 12, which suggest the existence of a relationship also in a large untested area. The authors should either provide some justification for this extrapolation, or limit the range of the plot to the tested area.
In summary, after these corrections and additions, I think the article is suitable for publication in Sustainability.
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsGeneral comments: In this study, effects of particle size and grading on the breakage of railway ballast were investigated using both laboratory test and numerical modelling. After carefully reading, the following comments and suggestions may be helpful to improve the manuscript.
Specific comments:
(1) What are the new findings of the present manuscript? The actuality and novelty of the present article must be clarified.
(2) The research status present in the manuscript is not clear. What research gap did you find from previous researchers in your field? Please explain them in the manuscript (e.g., introduction section).
(3) Abstract section: Abstract should be rewritten to make it more informative, e.g., using more quantitative data.
(4) Line 199: Fig. 4 (a) was not found! Please check it.
(5) Lines 208-209: It seems that all relevant microscopic parameters were inherited from previous studies. How could authors ensure that all these parameters can be directly used in the DEM model since the internal material properties can significantly affect the DEM parameters. Relevant statements are necessary in the manuscript if the same materials used in both the literature and this study.
(6) Figs. 12 and 14: What do the shadows with different colors mean? Do they stand for standard deviations? Please clarify them in the manuscript.
(7) Many grammatical errors have been found, e.g., line 15, “The results show that …” should be “The results showed that …”. Line 18, “Micromechanical analysis shows that …” should be “Micromechanical analysis showed that …”. Please check the full text carefully, find all errors and revise them.
Comments on the Quality of English LanguageMany grammatical errors have been found, e.g., line 15, “The results show that …” should be “The results showed that …”. Line 18, “Micromechanical analysis shows that …” should be “Micromechanical analysis showed that …”. Please check the full text carefully, find all errors and revise them.
Author Response
Please see the attachment
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsNo further comments
Reviewer 3 Report
Comments and Suggestions for AuthorsAll of the comments and suggestions have been addressed. The manuscript crrently can be considered to be accepted for publication.
