Recovery Strategies for Urban Rail Transit Network Based on Comprehensive Resilience

Round 1

Reviewer 1 Report

The reviewed article solves the current problem of increasing resistance to damage (interference) of urban railway transit networks that arise during emergency and unforeseen situations. Minimizing the propagation of an incident and quickly restoring system performance to the original service level to improve the resilience and safety of transportation systems is becoming increasingly relevant and is of both practical and scientific interest. The article title and keywords adequately reflect its content. In the abstract, the authors present the essence of the problem and its state, describe the research methods and models, the results obtained and conclusions on the work.

In the introduction, the authors substantiate the relevance of the problem, formulate the purpose and provide a literature review of relevant studies on the article topic, and also briefly formulate the objectives and the proposed research method. The second part is devoted to building a network, its topology, and service quality. Comprehensive indices for assessing the sustainability of the urban railway transport network are proposed, taking into account the network topology and the route selection. The third part presents a two-level model for restoring the railway transport network. The top-level model is an optimization model for deciding on the sequence of restoration of the metro network and with the aim of maximizing overall resilience in the event of interference that leads to station closure or disruption. The lower-level model is the shortest path model. Algorithms for implementing the two-level programming model are proposed. In the fourth section, the authors, using the example of a real urban railway transport network, present a study of the structure of the network and various strategies for its restoration. The simulation results are presented, their analysis and calculation of network stability are carried out. In the “Conclusions” section, the authors summarize the results obtained and provide conclusions on the work.

The article has been prepared in accordance with the instructions for authors and is relevant to the topic it is researching and publishing. In our opinion, the article corresponds to the topic “Strategies for the restoration of the urban rail transit network based on comprehensive sustainability” and is similar in type to the Preliminary Study.

Commentary

The article topic is interesting, in general the authors give good reasons for their models and conclusions, but there are some minor comments.

1. In section 3.3. The all-or-nothing distribution method was used to create the lower-level model. In our opinion, this choice requires justification.

2. The abstract states that the lower-level model is solved using a genetic algorithm but in Section 4.3. is indicated that this algorithm solves the top-level model, this fact requires clarification.

3. In section 4.3. states: “The Delphy-Entropy" weighting method was applied to determine the weights: passenger flow loss rate and network service efficiency. The combined weights of these two indicators were 0.5092 and 0.4908, respectively. Since the Delphi method is a subjective weighing method, and the entropy method is an objective weighing method, the mechanism of their combination requires explanation.

Comments for author File: Comments.pdf

Author Response

Dear Reviewer:

      Thank you very much for your comments and professional advice. These suggestions have greatly improved the rigor of the article.

      We will endeavor to improve the quality of the manuscript. According to your suggestions, we have made some adjustments to the content of the article, corrected the wrong parts, and reorganized the language and added flowcharts of the algorithms. I will present the details of the modifications one by one in the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Report on the manuscript “Recovery Strategies for Urban Rail Transit Network based on Comprehensive Resilience” by Mingming Zheng, Hanzhang Zuo, Zitong Zhou and Yuhan Bai

This paper develops an optimization model for measuring the resilience of urban rail transit networks taking topology and passenger travel choices into consideration. An integrated resilience index for urban rail transit networks is proposed, and a bi-level programming model with the objective of maximizing the cumulative integrated resilience during the degradation and recovery of rail network performance is introduced. In this model, the upper-level determines the optimal recovery sequence for failed sites under an interference event. In the lower-level, an all-or-nothing passenger assignment model is used which the objective of minimizing the traveller impedance. An experiment with five different incident scenarios on a real transport network of 164 nodes has been analysed, concluding that the integrated toughness-optimal restoration strategy is the best option.

Since the objective function is nonlinear and nonconvex, a genetic algorithm is used to solve the upper-layer model to determine the optimal network node recovery based on the integrated toughness index.

The paper is well written and the topic is clearly interesting, in particular, it is certainly suitable for being published at Sustainability.

However, I would like to suggest that the authors make the following changes:

The article presents two substantial lacks.

A)   There are no shared variables in the formulation of upper-level and lower-level models.

B)    The genetic heuristic has been described without any mention of the variables used in the formulation of upper-level and lower-level models. In fact, the proposed heuristic does not keep any parallelism with the global optimization model.

In the current state, I consider that the article should be rejected for publication at Sustainability.

Minor comments:

1)     Reference [18] on page 3, line 101 is misquoted in the text.

2) Figure 1 consists of five drawings that should be better explained in the text.

Change "a interference" by "an interference" in several places along the text

Author Response

Dear Reviewer:

        Thank you very much for your comments and professional advice. These suggestions greatly enhance the rigor of the article.

        Based on your suggestions, we have made major adjustments to the content of the article, corrected the two-layer planning model, and added an algorithmic flowchart. We present the details of the modifications one by one in the attached document.

Author Response File: Author Response.pdf

Reviewer 3 Report

Transport is one of the critical areas to improve the sustainability of cities, and its importance has been reflected in the UN Sustainable Development Goals for cities, which include among their goals that transport systems are safe, accessible to the entire population, and urbanization is inclusive through participatory management. This research is interested in the possibilities to improve the sustainability of urban mobility, analyzing, in particular, the urban rail transit network infrastructure needs to promote mobility in contexts of high demand of public space by different users and with a strong presence of informal commercial activities, based on the analysis of the dynamics of use in rail transit network recovery model,

Strenghts: The topic is important and current. The area is clearly linked to the issues of urban sustainability and major challenges facing public administration. The main virtue of the article is that the authors apparently worked on a well-thought-out research concept. Thus their work can be evaluated as a thorough scientific work. There are good and less good parts, but they are all linked together in a logical line of thought, and it becomes clear how they are related to each other, what the role of one is and what is the other. The article is clearly helpful in understanding the current topic it raises.

Weaknesses: It is a pity that the authors did not elaborate on the current widespread debates around making the big cities livelier, more sustainable. According to many experts, car sharing, e-mobility, environmentally friendly public transportation, and switching vehicles to electric or other eco-friendly drives can solve problems in urban transport, air pollution, over-traffic and parking problems.

Suggestions: I suggest that the study be supplemented with a brief introduction of the other latest efficient green solutions (such as the latest vehicle sharing services, cutting-edge technologies, satellite navigation and positioning, and mobile internet capabilities etc.) that can provide alternatives to metropolitan public transport and mitigate private cars and the need for parking spaces.

Author Response

Dear Reviewer:

Thank you very much for your comments and professional advice. These suggestions round out the article. Based on your suggestions, we have supplemented the article by adding a research background note of about 100 words. Your suggestions have been effective in pointing out the shortcomings of our manuscripts and improving the quality of the content. We have provided a detailed explanation in the attached document.

Author Response File: Author Response.pdf

Reviewer 4 Report

I would like to congratulate the authors for the research work they have in mind using a real-world urban rail transit network as an example and applying different recovery strategies: random recovery, node importance-based recovery, and comprehensive toughness-based recovery, across five common interference scenarios to analyze the recovery sequence of stations under each scenario.

The Introduction includes most of the literature review referring to significant scientific works in the field. The authors specify the novelty of this scientific work by correctly identifying the research context up to now. In this context, also explain what the major objective of the research is.

The methodology and the results obtained are logical (gradually developed), well-written, prepared and properly explained. In the elaboration of the scientific work, I appreciate the accuracy and discipline of the scientific approach.

The conclusions are expressed in the synthesis related to the results and I recommend their development from the perspective of public policy implications. I appreciate that the authors specified the limits of the research and stated the future research directions.

Author Response

Dear Reviewer:

        Thank you very much for your comments and professional advice. These suggestions round out the article. Meanwhile, thank you very much for recognizing the innovative nature of the manuscript, and we will work harder to improve the quality of the manuscript. Based on your suggestions, we have added more than 100 words to propose resilience optimization measures for the full life cycle of urban rail network disturbances from the perspective of transit policy, which improves the applicability of the study. We have provided a detailed description in the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

The paper is now certainly suitable for being published at Sustainability.