Analytical Procedures for the Evaluation of Infrastructural Measures for Increasing the Capacity of Railway Lines
Round 1
Reviewer 1 Report
The detailed information and advices are shown in the attachment, and please check them.
Comments for author File: 
Comments.pdf
Author Response
Dear Reviewer,
Thank you very much for your good review and your comments on our manuscript entitled “Analytical procedures for evaluation of the infrastructural measures for increasing the capacity of railway line”. Your comments were constructive, and we did our best to improve the paper based on your feedback. Please find more detailed responses below:
Point 1: (i) As mentioned in line 236, the solution adapted in the research is generated from the Slovak infrastructure manager 236 rules (D24), and then what is the technology innovative point of this paper? Is there any improvement made compared to the method in D24? If any, please make supplementary remarks in the manuscript. If not, this paper is just an engineering proposal report finished based on the existing method, then it will not be recommended for publication.
Response 1: This idea is very important and actual. It was incorporated into the conclusion of the manuscript.
Point 2: (ii) This paper is a little lengthy and verbose, which need to be streamlined, for example:
(ii-a) The last two paragraphs of ‘Introduction’ part are shown below: “The aim of the research is to propose procedures that will simply and accurately determine the quantification of benefits for increasing throughput performance of the line…… The aim of the research is to theoretically determine and practically apply analytical approaches to the evaluation of the throughput performance of railway lines……”
The above two paragraphs have similar expressions and contents, so it is recommended to be
rewritten into one single paragraph.
(ii-b) The first two paragraphs of ‘Literature overview’ section is shown below:
“Although capacity seems to be a self-explanatory term in common language, its scientific use may lead to substantial difficulties when it is associated to objective and quantifiable measures. It is a complex term that has numerous meanings and for which numerous definitions have been given. When referring to a rail context, it can be described as follows: ‘Capacity is a measure of the ability to move a specific amount of traffic over a de-117 fined rail line with a given set of resources under a specific service plan.’ [15].”
The above expression is too lengthy and redundant for a scientific paper.
Besides, the first two sections of this paper are ‘Introduction’ and ‘Literature overview’, as far as
I’m concerned, these two parts can be merged and streamlined into one section, for these parts take up too much space.
Response 2: The manuscript has been largely revised to consider the reviewer's comments. The focus of the research was explained in more detail in comparison with the current state of knowledge.
Point 3: This paper has lots of contents, but the readability needs to be improved, some of the expressions are a little confusing and have some faulty wordings, shown as follows.
Response 3: The manuscript has been largely revised to consider the reviewer's comments.
Point 4: There are some problems in the expression of the equations, for example: ...
Response 4: The equation has been revised to consider the reviewer's comments.
Point 5: Supplementary statements should be added for some figures, for example, the figure 2 refers to
the analysis of occupancy time for train sequences, but there is no additional statement on how to
calculated the occupancy time.
Response 5: The figures has been largely revised to consider the reviewer's comments.
Please note that we now also had the manuscript checked in terms of the English language, which resulted in improvements of the language.
Thank you again for the valuable review. We hope that we have been able to address your comments and questions in a satisfactory way.
Sincerely,
For the authors
Zdenka Bulkova
Reviewer 2 Report
Specific comments
Abstract
- Motivation in the beginning about the EU transport objectives could be shortened. It is also unnecessary to mention the EU regulations here.
- In RFC, there is R stands for Rail.
- In general, avoid using abbreviations in the abstract.
- Which methodology is used at the Railways of the Slovak Republic?
- In the end of the abstract, the authors state that the mentioned procedures are advantageous without providing examples of these advantages. Few words would be enough here.
Introduction
- In line 96, the authors state that for initial estimates, analytical methods can be used. A motivation for this statement would be good to include here, maybe with a reference to a relevant paper.
- Can the choice of Amber be explained? Is it because of data availability or planned future investments on this section?
- In line 109, brief introduction of the methodology that is used at the Railways of the Slovak Republic or maybe (additionally) provide a reference.
Literature review
- The sentence in line 119-120 should be corrected.
- The review of existing research/literature should be more homogenous. The current review seems like a listing of some studies from here and there. The authors can try to include brief descriptions of the most relevant results, establishing more fluid connections between them and the present paper.
- In line 153, “train traffic diagram” à train timetable.
- Railroad versus railway, stick to either US or else UK terms.
- In 171, “timetable stability” -> more common terms in the literature are timetable robustness/resilience.
- At the end of this section, the summary can be supported with a table of the literature comparing them and the current paper (e.g., dis-/advantage).
Materials and methods
- Consistent capitalization when listing items as bullet points. Same remark is valid throughout the paper.
- In line 237, what is D24?
- Figure 2 deserves more description and explanation. Can it be simplified?
- In line 253, Ni should be N_i. Same remark for NR -> N_R.
- What is “i”? you mean type i.
- What is the difference between N_R and N_i?
- In Line 282, By compiling.
- T_br instead of Tbr. Same for To -> T_o and Ts -> T_s
- In line 293, instead of device -> assets.
- In equation (5), why is the unit train*T-1? A sentence explaining this would be good.
- In equation (6), what is t_rus?
Capacity Results
- In the first paragraph, a motivation of the choice of the case study can be given.
- Any specific source of the data in table 2. If the authors have constructed this input data, a brief explanation of how is appreciated.
- In line 340, interstationary.
- Sentences like the one in 343 about using principles of probability and statistics are vague. A more precise sentence would specify which principles are used.
- In line 351, boudling -> bundling.
- In line 352, period, occupancy. There are many simple spelling mistakes that could be avoided. Authors can use any spelling checker to fix most of them.
- The results from table 4 need more description to help the reader understand what is presented. Same remark for table 6.
- In table 5, throughput utilization is in %.
- The results should be discussed and analysed, e.g., are they plausible? Comparison of the resulting throughput performances, any possible explanations/speculations? Also compared to the data in table 2.
- Many of the tables can be included in an appendix.
Capacity measures
- In table 8, I do not understand why arc number 4 has multiple values.
- Briefly introduce the notations that are used in equations 7, 8 and 9.
- Same remark for use of appendix for both table 9, 11, 13, 15, 17 and 20
- Much of the description of the different capacity measures A/B 1-5 can be shortened and keep to the most relevant details for the calculations. Discussions and analysis of the results would instead be more interesting for the conclusions of the study.
Discussion
- A summary table (can be in the appendix) presenting the main results from the different measures would be good to have. Also this can help draw some useful conclusions as for the effects of the different measures in terms of throughput performance.
- In line 638, the construction OF …
- In line 691, a level crossing.
- Some of the limitations of the methodology can be presented and discussed. Maybe in a section before presenting further developments of the research.
Conclusion
- In line 710, … planning ..
- further developments of the research in the discussion is more relevant in the conclusion.
General comments
- Many language mistakes can be easily correct. Authors are invited to read the paper again and check these mistakes. The text must be largely revised to make the sentences understandable. Keep sentence short and simple (to understand)!
- Headlines should be consistent in capital letters, e.g., Literature overview, Materials and Methods.
- Terminology is not consistent, use the same terms throughout the paper, e.g., railway, railroad.
- Include more diversity in the articles you are citing. Sounds very narrow/specific (e.g., to Slovakia).
- Result analysis and conclusions are shallow, more thorough practical interpretation of the results is needed.
Author Response
Dear Reviewer,
Thank you very much for your good review and your comments on our manuscript entitled “Analytical procedures for evaluation of the infrastructural measures for increasing the capacity of railway line”. Your comments were constructive, and we did our best to improve the paper based on your feedback. Please find more detailed responses below:
Point 1: Abstract
- Motivation in the beginning about the EU transport objectives could be shortened. It is also unnecessary to mention the EU regulations here.
- In RFC, there is R stands for Rail.
- In general, avoid using abbreviations in the abstract.
- Which methodology is used at the Railways of the Slovak Republic?
- In the end of the abstract, the authors state that the mentioned procedures are advantageous without providing examples of these advantages. Few words would be enough here.
Response 1: All comments were incorporated into the abstract, including a note on the nature of the Railways of the Slovak Republic methodology.
Point 1: Introduction
- In line 96, the authors state that for initial estimates, analytical methods can be used. A motivation for this statement would be good to include here, maybe with a reference to a relevant paper.
- Can the choice of Amber be explained? Is it because of data availability or planned future investments on this section?
- In line 109, brief introduction of the methodology that is used at the Railways of the Slovak Republic or maybe (additionally) provide a reference.
Response 2: The introduction has been largely revised to consider the reviewer's comments. Comments regarding the methodology of the Railways of the Slovak Republic and its analytical character, as well as the selection of the bottleneck section of the RFC "Amber" were incorporated.
Point 3: Literature review
- The sentence in line 119-120 should be corrected.
- The review of existing research/literature should be more homogenous. The current review seems like a listing of some studies from here and there. The authors can try to include brief descriptions of the most relevant results, establishing more fluid connections between them and the present paper.
- In line 153, “train traffic diagram” à train timetable.
- Railroad versus railway, stick to either US or else UK terms.
- In 171, “timetable stability” -> more common terms in the literature are timetable robustness/resilience.
- At the end of this section, the summary can be supported with a table of the literature comparing them and the current paper (e.g., dis-/advantage).
Response 3: We revised the text explaining the sources for the topic being solved, as well fixed the terms. However, the summarization did not require the creation of a comparison table as requested by the reviewer.
Point 4: Materials and methods
- Consistent capitalization when listing items as bullet points. Same remark is valid throughout the paper.
- In line 237, what is D24?
- Figure 2 deserves more description and explanation. Can it be simplified?
- In line 253, Ni should be N_i. Same remark for NR -> N_R.
- What is “i”? you mean type i.
- What is the difference between N_R and N_i?
- In Line 282, By compiling.
- T_br instead of Tbr. Same for To -> T_o and Ts -> T_s
- In line 293, instead of device -> assets.
- In equation (5), why is the unit train*T-1? A sentence explaining this would be good.
- In equation (6), what is t_rus?
Response 4: The text in the chapter was reorganized, rearranged, while the own research objectives were specified and supplemented. Qualitative indicators of throughput performance are explained and supplemented with a graph. Formulas and units of quantities have been corrected.
Point 5: Capacity Results
- In the first paragraph, a motivation of the choice of the case study can be given.
- Any specific source of the data in table 2. If the authors have constructed this input data, a brief explanation of how is appreciated.
- In line 340, interstationary.
- Sentences like the one in 343 about using principles of probability and statistics are vague. A more precise sentence would specify which principles are used.
- In line 351, boudling -> bundling.
- In line 352, period, occupancy. There are many simple spelling mistakes that could be avoided. Authors can use any spelling checker to fix most of them.
- The results from table 4 need more description to help the reader understand what is presented. Same remark for table 6.
- In table 5, throughput utilization is in %.
- The results should be discussed and analysed, e.g., are they plausible? Comparison of the resulting throughput performances, any possible explanations/speculations? Also compared to the data in table 2.
- Many of the tables can be included in an appendix.
Response 5: The remarks were incorporated into the results of the manuscript. The motivation remark of the choice of the case study was given. Tablets 4 and 6 were described in more detail. The spelling mistakes are corrected.
Point 6: Capacity measures
- In table 8, I do not understand why arc number 4 has multiple values.
- Briefly introduce the notations that are used in equations 7, 8 and 9.
- Same remark for use of appendix for both table 9, 11, 13, 15, 17 and 20
- Much of the description of the different capacity measures A/B 1-5 can be shortened and keep to the most relevant details for the calculations. Discussions and analysis of the results would instead be more interesting for the conclusions of the study.
Response 6: In our opinion, shortening the text and arranging the tables in a different way would disrupt the sequence and sequence of the calculations and thereby reduce comprehensibility. For this reason, we decided to leave the structure of the text and tables unchanged. The remaining comments have been incorporated.
Point 7: Discussion
- A summary table (can be in the appendix) presenting the main results from the different measures would be good to have. Also this can help draw some useful conclusions as for the effects of the different measures in terms of throughput performance.
- In line 638, the construction OF …
- In line 691, a level crossing.
- Some of the limitations of the methodology can be presented and discussed. Maybe in a section before presenting further developments of the research.
Response 7: The presentation the main results from the different measures are evaluated in table 24. The limitations of the methodology are discussed. The spelling comments have been incorporated.
Point 8: Conclusion
- In line 710, … planning ..
- further developments of the research in the discussion is more relevant in the conclusion.
Response 8: The remarks were incorporated into the conclusion of the manuscript.
Point 9: General comments
- Many language mistakes can be easily correct. Authors are invited to read the paper again and check these mistakes. The text must be largely revised to make the sentences understandable. Keep sentence short and simple (to understand)!
- Headlines should be consistent in capital letters, e.g., Literature overview, Materials and Methods.
- Terminology is not consistent, use the same terms throughout the paper, e.g., railway, railroad.
- Include more diversity in the articles you are citing. Sounds very narrow/specific (e.g., to Slovakia).
- Result analysis and conclusions are shallow, more thorough practical interpretation of the results is needed.
Response 9: The general comments are incorporated into the manuscript.
Please note that we now also had the manuscript checked in terms of the English language, which resulted in improvements of the language.
Thank you again for the valuable review. We hope that we have been able to address your comments and questions in a satisfactory way.
Sincerely,
For the authors
Zdenka Bulkova
Reviewer 3 Report
This paper presents a method to estimate the capacity based on the anticipated timetable. The study seems interesting; however, it is difficult to understand as many concepts and figures are not adequately explained. For example, figures 2 and 4 need to be explained. The capacity measures in section 5 also need to be better explained (e.g., how the train operations will be conducted with the new measures). Some minor issues: the sentence in lines 285-286 seems incomplete.
Author Response
Dear Reviewer,
Thank you very much for your good review and your comments on our manuscript entitled “Analytical procedures for evaluation of the infrastructural measures for increasing the capacity of railway line”. Your comments were constructive, and we did our best to improve the paper based on your feedback. Please find more detailed responses below:
This paper presents a method to estimate the capacity based on the anticipated timetable. The study seems interesting; however, it is difficult to understand as many concepts and figures are not adequately explained. For example, figures 2 and 4 need to be explained. The capacity measures in section 5 also need to be better explained (e.g., how the train operations will be conducted with the new measures). Some minor issues: the sentence in lines 285-286 seems incomplete.
In Figure 2, we have added additional characteristics in the text that belong to the occupation time for individual train sequences. Figure 4 shows the situation from these descriptions. We have added to the text a more detailed specification that the type train in the given case is a Freight running train (Fr). In chapter 5, we have added mentions that newly determined operating intervals were used and driving times were shortened. This is the main benefit of the assessed infrastructure measures. The sentence in lines 285-286 has been edited.
Please note that the manuscript was checked in terms of the English language, which resulted in improvements of the language.
Thank you again for the valuable review. We hope that we have been able to address your comments and questions in a satisfactory way.
Sincerely,
For the authors
Zdenka Bulkova
Reviewer 4 Report
1）The method is used to evaluate the total throughput performance of the consider rail line. However, in most case, the bottlenecks of the throughput performance should be found for further improving the throughput performance.
2) The evaluation results mostly depend on the probability of the each category train running, and the probability of running a sequence of trains. However, these two usually change with the passenger and freight demands.
3) The method is not complicated and also is not a new method, so what’s the contribution of the research regarding with the method?
4) In the section 5, lots of cases of adjusting the rail infrastructure are analyzed. Is it possible to find a better adjustment strategy based on the evaluation results on the current situation of rail infrastructure?
Author Response
Dear Reviewer,
Thank you very much for your good review and your comments on our manuscript entitled “Analytical procedures for evaluation of the infrastructural measures for increasing the capacity of railway line”. Your comments were constructive, and we did our best to improve the paper based on your feedback. Please find more detailed responses below:
1）The method is used to evaluate the total throughput performance of the consider rail line. However, in most case, the bottlenecks of the throughput performance should be found for further improving the throughput performance.
2) The evaluation results mostly depend on the probability of the each category train running, and the probability of running a sequence of trains. However, these two usually change with the passenger and freight demands.
3) The method is not complicated and also is not a new method, so what’s the contribution of the research regarding with the method?
4) In the section 5, lots of cases of adjusting the rail infrastructure are analyzed. Is it possible to find a better adjustment strategy based on the evaluation results on the current situation of rail infrastructure?
1) Bottlenecks are searched for a certain track section, i.e. for the evaluated part of the railway infrastructure. Of course, the mentioned procedures presuppose the determination of the assumed bottleneck, which is the interstationary section. In this section, the proposed procedures are carried out.
2) The assessment methodology is designed for track lines with mixed traffic. The priority of passenger trains is not evaluated, but their number, which indicates the required share of capacity consumption.
3) The benefit of the proposed methodology is proof that the analytical procedures for determining the capacity are sufficient for certain assessment cases, for example planned investments in railway infrastructure, i.e. for the assessment of variants of the implementation of construction measures or the modernization of interlocking equipment. The benefit is that the setting of the critical value of the degree of occupation of the infrastructure is of fundamental importance for the use of capacity procedures in practice, which we tried to demonstrate in a practical application.
4) The strategy for evaluating the results of the current state of the infrastructure can take several forms. For example, it is possible to evaluate the realised timetables (how the operation folows the plan) and all qualitative parameters of this realised timetable, for example the analysis of the degree of occupation. However, we believe that in order to obtain comparability of results in the current state and in the outlook after the application of infrastructure measures, it is better to use the same methodology for both variants.
Please note that the manuscript was checked in terms of the English language, which resulted in improvements of the language.
Thank you again for the valuable review. We hope that we have been able to address your comments and questions in a satisfactory way.
Sincerely,
For the authors
Zdenka Bulkova
Round 2
Reviewer 1 Report
As far as I see from the manuscript, the analytical procedures for throughput performance proposed are entirely from the methodology of Railways of the Slovak Republic (introduced on the internal Regulation D24) and other previous researches, and there is no more innovation rather than reusing and resetting the critical value of occupation rate So. Therefore, I am sorry to inform the authors that this paper does not meet the requirements of Sustainability.
Author Response
Dear Reviewer,
Thank you very much for your critical review and your comments on our manuscript entitled “Analytical procedures for evaluation of the infrastructural measures for increasing the capacity of railway line”. Your comments were constructive, and we did our best to improve the paper based on your feedback. Please find responses below:
As far as I see from the manuscript, the analytical procedures for throughput performance proposed are entirely from the methodology of Railways of the Slovak Republic (introduced on the internal Regulation D24) and other previous researches, and there is no more innovation rather than reusing and resetting the critical value of occupation rate So. Therefore, I am sorry to inform the authors that this paper does not meet the requirements of Sustainability.
The authors are of the opinion that the controversy about setting the critical value of infrastructure occupation rate is of fundamental importance for use in capacity procedures in practice, which we tried to demonstrate in a practical application.
Please note that the manuscript was checked in terms of the English language, which resulted in improvements of the language.
Thank you again for the valuable review. We hope that we have been able to address your comments and questions in a satisfactory way.
Sincerely,
For the authors
Zdenka Bulkova
Reviewer 3 Report
I believe that the authors have improved the paper and adequately addressed my previous concerns. I have no more concerns.
Author Response
Dear reviewer,
Thank you very much for your time and notes, which contributed to the improvement of our manuscript.
Best regards for authors Zdenka Bulkova
Round 3
Reviewer 1 Report
We think the novelty is critical to a paper, however, as we mentioned in the previous comments, the analytical procedures for throughput performance proposed are mainly from the methodology of Railways of the Slovak Republic (introduced on the internal Regulation D24) and other previous researches, and we think the new method for determining optimal and critical throughput performance in this paper is not that significant. Thus I am sorry to inform the authors that this revised paper still does not meet the requirements of Sustainability.
Author Response
Dear reviewer,
Many thanks for your time and notes for our manuscript. We are very so sad that your opinion is negative for our research work. We understand your comments that used methodology for rail capacity is based on the using method (ŽSR D24). But our proposals for to increase capacity are oriented for Slovak railways conditions, therefore using new simulations methods or create new methodology might not lead to correct results in ŽSR conditions. In our research we proposed some solutions how to increase capacity on the rail line, which is part of international part of TEN network, but these possibilities of reconstruction are limited. We mean that the analytic methodology of ŽSR is correct for cooperations for our solutions, that they will make it possible to improve the operational parameters of the solved rail line.
Best regards for authors Zdenka Bulkova
