An Efficient Numerical Model to Predict the Mechanical Response of a Railway Track in the Low-Frequency Range
Round 1
Reviewer 1 Report
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Author Response
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Reviewer 2 Report
In all article “french” should be changed to “French”;
“Punctual mass” sounds strange to me – explanation should be provided;
L 70 – start new sentence with capital letter: “Beam-like structure…”;
L 133- 134 – “…track inertia forces are negligible in front of vehicle’s inertia …” – consider reformulation to: “…track inertia forces are negligible compared to of vehicle’s inertia …;”
L 137 change order of frequencies in [50;30 Hz] to [30;50 Hz];
L 147, 183 – evidently: “reference plane”, “symmetry plane” should be written;
L230 –Start the sentence with capital letter “An L∞ ….”;
Page 11, top – put together “it self” (correct “itself”);
Page 12 – Why is the Figure 9 placed inside the paragraph – please, move it after the paragraph; similarly, Table 2 is inside the paragraph;
L 269 – correct “implemented” to “implemented”;
The main objective of the work was to propose an efficient methodology that support railway vehicles admission procedure and that allows to define new rules for traffic conditions based on the evaluation of the fatigue in the rail. The idea is to quickly provide relevant information on the capacity of the railway to bear the vehicle load.
However, I miss the demonstration of using the method in real practice for real vehicles used on French railways – perhaps this might be done within the following study in which it is expected to do investigations in order to characterize the lateral behaviour of the track.
Author Response
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Reviewer 3 Report
The manuscript “An efficient numerical model to predict the mechanical response of a railway track in the low-frequency range” presents theoretical studies in the field of mechanical engineering. The paper presents a development of a model for investigation of the mechanical response of the track in the low-frequency range. The model is aimed to be used for vehicles admission on the railway network. It is important both for operational safety and maintenance. However, the track and the train models are not novel. Moreover, they are decoupled. The novelty of the research should be highlighted, and the difference from the conventional approach should be mentioned. The aim of the research is not clearly fulfilled.
The paper could be published in MDPI after the major improvement that takes into account the following remarks:
- The topic scope “…to predict the mechanical response of a railway track…” is very wide but only the bending and shear stresses response is considered. Actually, the rail fatigue failure is relatively seldom one compared to more frequent ballast failures due to low frequency interaction.
- The negligible effect of track inertia forces due to high track stiffness and damping is stated. It is true for rail normal stresses but not for ballast loading, especially in the case of sleeper voids or unsupported sleepers. Please note in the discussion and the literature review by referring to the corresponding papers on void interaction in MDPI Journals (Mechanism of Sleeper–Ballast Dynamic Impact and Residual Settlements Accumulation in Zones with Unsupported Sleepers, Identification of Sleeper Support Conditions Using Mechanical Model Supported Data-Driven Approach etc.)
- The model takes into account only geometrical irregularities in their influence on the rail stresses, however, the inhomogeneities of the sleeper support ( variable stiffness and voids) cause higher rail deflections and therefore tensions than geometrical ones.
- What sense has the section “3.1.1. Comparison…” if it was assumed that “… low-frequency range, track inertia forces are negligible….”. The equal dynamic and static responses of the track follow from assumption and do not need calculation.
- The comparison of the developed model in terms of the accuracy/efficiency with the conventional approach that was mentioned in the intro ’…simplified analytical works…’ would be plausible.
- The objective of the research contains “…an efficient methodology ….” and “…new rules …”. However, the conclusions contain none of them.
- The Conclusion should be systematized is a separate section from the discussion.
Author Response
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Reviewer 4 Report
Notes in the attached file
Comments for author File: Comments.pdf
Author Response
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Round 2
Reviewer 1 Report
Corrections have been made.
Reviewer 3 Report
The manuscript is significantly improved and could be published.
