Riding Comfort Evaluation Based on Longitudinal Acceleration for Urban Rail Transit—Mathematical Models and Experiments in Beijing Subway
Round 1
Reviewer 1 Report
Dear authors I read your paper and these are my suggestions:
- The second chapter "Field data description" is more appropriate to be included in chapter 4.
- In chapter 3.1 you refer to figure 2. I think it is figure 3.
- Equation 5 does not correctly reflect equation 4. Repeat the calculation
- I don't find a connection between your mathematical models and the concept Mobility-as-a-Service. Please correct your conclusion
Author Response
We have made revisions point by poinnt. Please see the attachment. Thanks!
Author Response File: 
Author Response.pdf
Reviewer 2 Report
This paper adopts the measured longitudinal acceleration data and passenger’s feedback data in the Beijing subway to develop a fuzzy set model. The validation of the proposed model is verified by the questionnaire and measurement data. Generally, this is good work with the potential application to the further assessment of riding comfort. The organisation and the presentation are quite good. In my point of view, this paper could be accepted for publication by addressing the following technical and editorial issues.
In the introduction, it is suggested that the author should give a general view regarding the main factors affecting the operation safety and passenger comfort, from the vehicle-track [#1], overhead system [#2], ground-borne vibration [#3] as well as the environment [#4] at the beginning.
[#1] S. Iwnicki, M. Spiryagin, C. Cole, T. (Timothy) McSweeney, Handbook of railway vehicle dynamics, Second Edition, CRC Press, 2019.
[#2] Song Y, Liu Z, Rønnquist A, Nåvik P, Liu Z. Contact wire irregularities stochastics and effect on the high-speed railway pantograph-catenary interaction. IEEE Transactions on Instrumentation & Measurement, 2020, DOI: 10.1109/TIM.2020.2987457.
[#3] Kaewunruen, Sakdirat, and Victor Martin. "Life cycle assessment of railway ground-borne noise and vibration mitigation methods using geosynthetics, metamaterials and ground improvement." Sustainability 10.10 (2018): 3753.
[#4] Wang, Z., Song, Y., Yin, Z., Wang, R., & Zhang, W. (2019). Random response analysis of axle-box bearing of a high-speed train excited by crosswinds and track irregularities. IEEE Transactions on Vehicular Technology, 68(11), 10607-10617.
In the fourth Line under Figure 2, it would be more professional to replace ‘acceleration sensor’ with ‘accelerometer’.
Please clarify the meaning of the sentence ‘Here, the accelerating rate actually represents the variations of train acceleration between two time units (or jerk).’
In section 3, please modify the grammar mistake in the sentence ‘...In short, if acceleration rate is greater than the scale the human body can tolerate, passengers will feel uncomfortable. In some research [10], the riding comfort is evaluated by the average acceleration rate...’. please add ‘the’ in front of acceleration. ‘that’ is missing after ‘scale’. In ‘some researches’, why only one paper is cited here?
The questionnaire data in Section 4.2 is quite important for the training and verification of the model. The author should give more details regarding this, such as how many samples in one group?
In addition, the reviewer is a bit doubtful whether the passenger exactly understood what the riding comfort was. The riding comfort analysed in this paper is mainly caused by the vibration of the carbody, but the passenger may include some other factors such as the congestion.
The future tense in some texts is misused. Please modify.
There are many grammar mistakes and inappropriate expressions in the whole paper. Please carefully check the texts.
Author Response
We have made revisions point by point by your valuable suggestions. Please see the attachment. Thanks!
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Thanks for the elaborate response. I think all my comments have been properly addressed in both of the cover letter and the revised manuscript. I recommend the publication of the paper in the current version.
