Sensitivity Analysis of Bogie Wheelbase and Axle Load for Low-Floor Freight Wagons, Based on Wheel Wear

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This work presents a numerical analysis about the life of a railway wheels used for low-floor freight wagons. In the model the contact fatigue and wear are incorporated by considering vehicle speed, load characteristics, materials properties, rail and wheel geometry, etc. The topic addressed by the paper is relevant to the scope of the journal, nevertheless several weaknesses are presented and then a minor revision is needed before publication.

The numerical analysis lacks verification, which would be the comparison with other numerical method or commercial simulation software, or the tested data.

Consider provide some discussion on the intermediate variables and process rather than presenting the results directly. Such as the fatigue index FI_sur, the wear coefficient, the pressure…

It is not necessary to present the basic equations the main text, e.g., the Hertzian solution of Eqs.27-36. Maybe is can be put in the appendix part. In the current form the model is too trivial to present valuable information.

Similarly, equations 53-55 should be merged into an equation by using curly brace.

Figure 2 is not clear enough, try use larger font size numbers and letters for annotation.

Comments on the Quality of English Language

Please try to improve the language as much as possible to make it more concise.

Author Response

Dear Reviewer #1:

Thank you for reviewing the paper and for your comments. We attach a document with the answers to each point.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The contribution is oriented towards the very interesting area of ​​railway transport. And that both from the point of view of traffic safety and the economy of traffic. The post has a classic structure. The title of the paper is catchy enough, the abstract very well and succinctly describes the given issue. The text of the contribution is divided into five basic parts. The individual parts of the contribution are balanced. The English used is understandable in my opinion. However, I recommend going through the text and removing minor errors (for example, and railway wheels, etc.). The theoretical assumptions of the described problem are described very well. The tables, images and graphs used are clear and appropriately complement the text of the presented issue. The mathematical apparatus used is sufficient, it is error-free and describes a well-presented issue. The procedures used were applied correctly. I really appreciate the list of symbols and marks used and the extensive bibliography.

 Thoughts on addition/clarification:

·         Were any appropriate experiments also carried out as part of the research work?

·         Alternatively, did the authors draw on results from already conducted experimental studies? E.g. correlation analysis between simulation model, operational data and wheel wear rate. I believe that it is very important for the given problem to analyse data from truck operation, including axle loads, speeds, trajectories and wheel wear, etc. It is very suitable for experiments to include the use of sensors and monitoring systems on tracks to monitor the dynamic responses of the cars and wheel wear.

·         Was or will the compiled algorithm be calibrated, compared with data from real operation?

·         When creating the algorithm, did the authors think about uniform or uneven axle load?

·         In their work, the authors also focused on new technologies to produce wheels and rails (higher quality materials and technology). This is one of the other ways to reduce wear and tear.

·         Will it be possible to include the obtained outputs in commercial specialized tools for the dynamics of railway vehicles, e.g. ADAMS/Rail?

·         Were outputs for the needs of vehicle designers derived from the work performed, or recommendations for regular maintenance of vehicles?

·         Based on the work carried out, will recommendations for the introduction of weighing systems and the correct distribution of loads in trucks be drawn up for carriers?

·         What subsequent work will the authors implement, e.g. to refine the simulation technique, etc.?

  Overall, I can state that this is an original, very carefully prepared contribution with great explanatory power. The presented methodologies, procedures and results will be very interesting both for experts in the presented area and for the wider technical public. 

Comments on the Quality of English Language

There are a few small mistakes in the article, for example in the abstract "a railway wheels", I believe it should be correctly "railway wheels" or "a railway wheel". It's nothing serious.

Author Response

Dear Reviewer #2:

Thank you for reviewing the paper and for your comments. We attach a document with the answers to each point.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors have addressed most of my comments.

Comments on the Quality of English Language

 English Language has been improved.

Author Response

Dear Reviewer #1,

Thank you for reviewing our manuscript again. You have helped us to improve our manuscript to a great extent.

Yours sincerely,

David S. Pellicer & Emilio Larrodé.