Development and Operation of Track Condition Monitoring System Using In-Service Train
Round 1
Reviewer 1 Report
This method seems to be approriate as long as you simply want to detect "poor track geometry" without touching safety relevant failures. These still must be measured by a track recording car.
Concerning your results:
In both analysed sections a maintenance work is marked in 07/2022 in figures 5 and 6 analysing the longitutdinal level. This is obviously a through-going tamping action (do you know it in detail?). In your discussion of the achieved results, you mention that in the first section, the maintenance was good and you see it in your data while the one in section 2 was poor quality (as your data did not react on it) . Is this feasible when it was the same maintenance?
In figure 8 and 9, you present the results for the lateral direction forthe same sections. There is a maintenance in 11/21, I think tamping again as this action would improve the geometry also in lateral direction. Again: Is this feasible? Why is this maintenance not mentioned in figures 5 and 6. And: if it is introduced, is your conlusion still valid?
Generally, I think it is very brave to base your conlusions in both cases exactly in a time frame where you miss data for almost 6 month.
Chapter 5 is interesting.
Author Response
Thank you very much for your careful peer review.
1. This method seems to be appropriate as long as you simply want to detect "poor track geometry" without touching safety relevant failures. These still must be measured by a track recording car.
The method proposed in this paper is not necessarily intended to replace measurement by track recording car. It is proposed as a system that complements measurements by track recording car, which can only be carried out once a year, and enables more efficient maintenance. In some regional railways, measurement by the track recording car is not possible and a track recording trolly is used. In such cases, problems may arise in accurately ascertaining the condition of the track, as live loads do not act on the track. The proposed system is effective for such railway operators. Track described in this paper are not measured by the track recording car, but the track recording trolly. The following additions have been made in "Conclusions".
"This system can be used in conjunction with track recording car measurement data for efficient maintenance."
2. In both analysed sections a maintenance work is marked in 07/2022 in figures 5 and 6 analysing the longitudinal level. This is obviously a through-going tamping action (do you know it in detail?). In your discussion of the achieved results, you mention that in the first section, the maintenance was good and you see it in your data while the one in section 2 was poor quality (as your data did not react on it) . Is this feasible when it was the same maintenance?
As you point out, it is unlikely to occur that the maintenance in the first section was good and the maintenance in the second section was of poor quality. Figures 5 and 6 show the maximum values for the 100 m section. Therefore, if track irregularities generating large accelerations are included in the maintenance section, the effect of maintenance should be confirmed. On the other hand, if the track irregularity was not included in the maintenance section, no decrease in vibration acceleration could be observed.
Unfortunately, the railway operators do not provide detailed information of the maintenance work. It is therefore not possible to comment on the details on the maintenance work. The railway operator has confirmed that maintenance work is being carried out in the section concerned.
The following additions are made to clarify above situation.
Page:8
"Track maintenance was performed in July 2022, but the vertical acceleration of the car-body has not decreased since then. Figures 5 and 6 show the maximum values for the 100 m section. Therefore, if track irregularities generating large vertical accelerations are included in the maintenance section, the effect of maintenance should be confirmed. On the other hand, if the track irregularity was not included in the maintenance section, no decrease in vibration acceleration could be observed. The details of the maintenance works shown in figures 5 and 6 were not provided by the railway operator. It is therefore necessary to re-examine why maintenance effectiveness cannot be confirmed in the section shown in Fig. 6, based on future measurement data and detailed information on the new maintenance works."
3. In figure 8 and 9, you present the results for the lateral direction for the same sections. There is a maintenance in 11/21, I think tamping again as this action would improve the geometry also in lateral direction. Again: Is this feasible? Why is this maintenance not mentioned in figures 5 and 6. And: if it is introduced, is your conclusion still valid?
As you pointed out, the tamping work is expected to reduce the amount of track irregularities in both vertical and lateral directions, resulting in lower vertical and lateral accelerations. However, the effect of the maintenance work on 21 November 2021 cannot be clearly seen in Figure 6. According to the information of maintenance work from the railway operator, tamping work was not included in the maintenance work on 21 November 2021,
4. Generally, I think it is very brave to base your conclusions in both cases exactly in a time frame where you miss data for almost 6 months.
It is true that missing data for 6 months may have a significant impact on the accuracy of the diagnosis. Future revalidation should be carried out on the basis of data without the missing data period.
The following text has been added in Section 3.3．
"Missing data for 6 months may have a significant impact on the accuracy of the diagnosis. Future revalidation should be carried out on the basis of data without the missing data period."
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Nice work by the authors - clear objectives with adequate data and supporting conclusions. Please see some comments to improve the quality of the manuscript:
- The abstract can be improved with a couple sentences about key results at the end of the abstract.
- The authors presented the data before and after maintenance, showing reduction in the vertical acceleration. It would be of interest to readers to show the before and after maintenance to correlate and also for authors to comment why the acceleration decreased.
- Is the velocity or acceleration normalized based on the speed of the train? It is understandable that if the train is running faster for a section compared to other sections, the same defect will result in more acceleration. This could also happen when two different trains are running at different speeds on the same sections.
- Why is 3 m/s2 considered very high value? What are the consequences?
Author Response
Thank you very much for your careful peer review.
1. The abstract can be improved with a couple sentences about key results at the end of the abstract.
The following additions are made
"Filed test results showed that sections with degraded tracks were identified using car-body vibration data. The track degradation trend can be constructed using the results obtained. Furthermore, the study demonstrated that the track maintenance effect could be confirmed. A method for improving in train position using yaw angular velocity is proposed. The track irregularity position can be shown more clearly by monitoring the track condition using position-corrected data using the proposed method. It is also shown that the time-frequency analysis of measured car-body vertical acceleration is effective for evaluating the track condition more clearly."
2. The authors presented the data before and after maintenance, showing reduction in the vertical acceleration. It would be of interest to readers to show the before and after maintenance to correlate and also for authors to comment why the acceleration decreased.
It is unlikely to occur that the maintenance in the first section was good and the maintenance in the second section was of poor quality. Figures 5 and 6 show the maximum values for the 100 m section. Therefore, if track irregularities generating large accelerations are included in the maintenance section, the effect of maintenance should be confirmed. On the other hand, if the track irregularity was not included in the maintenance section, no decrease in vibration acceleration could be observed.
Unfortunately, the railway operators do not provide detailed information of the maintenance work. It is therefore not possible to comment on the details on the maintenance work. The railway operator has confirmed that maintenance work is being carried out in the section concerned.
The following additions are made to clarify above situation.
Page:8
"Track maintenance was performed in July 2022, but the vertical acceleration of the car-body has not decreased since then. Figures 5 and 6 show the maximum values for the 100 m section. Therefore, if track irregularities generating large vertical accelerations are included in the maintenance section, the effect of maintenance should be confirmed. On the other hand, if the track irregularity was not included in the maintenance section, no decrease in vibration acceleration could be observed. The details of the maintenance works shown in figures 5 and 6 were not provided by the railway operator. It is therefore necessary to re-examine why maintenance effectiveness cannot be confirmed in the section shown in Fig. 6, based on future measurement data and detailed information on the new maintenance works."
3. Is the velocity or acceleration normalized based on the speed of the train? It is understandable that if the train is running faster for a section compared to other sections, the same defect will result in more acceleration. This could also happen when two different trains are running at different speeds on the same sections.
As you point out, train speed affects car-body acceleration. The data presented in this paper include the effect of this train speed change. The authors also propose a more accurate evaluation method that does not depend on the effect of train speed (Ono, H.; Tsunashima, H.; Takata, T.; Ogata, S. Development and operation of a system for diagnosing the condition of regional 486 railways tracks. Mechanical Engineering Journal, Article ID 22-00239, Advance online publication January 20, 2023, Online ISSN 487 2187-9745, doi.org/10.1299/mej.22-00239.). The sections evaluated in this paper have not been corrected for the effect of train speed, as the speed changes were small. Also, if the in-service train to be measured changes, the data to be measured will also change. For this reason, measurements are always taken on the same train.
The following additions are made to clarify above situation in Section 3.2.
"The data presented in this paper include the effect of this train speed change. The authors also propose a more accurate evaluation method that does not depend on the effect of train speed[21]. The sections evaluated in this paper have not been corrected for the effect of train speed, as the speed changes were small (AVE: 35.0km/h, SD: 5.3km/h at 1.15km, AVE: 30.5km/h, SD: 4.7km/h at 1.45km). Also, if the in-service train to be measured changes, the data to be measured will also change. For this reason, measurements are always taken on the same train."
AVE: average, SD: standard deviation
The following additions are made in Figure 4.
"Averaged speed profile for all runs is shown at the bottom of the diagram. AVE: 35.0km/h, SD: 5.3km/h at 1.15km, AVE: 30.5km/h, SD: 4.7km/h at 1.45km."
4. Why is 3 m/s2 considered very high value? What are the consequences?
Shinoda et. al pointed out that if the vertical acceleration exceeds 2.8 m/s2 in the driver's cab, track maintenance should be carried out as soon as possible. For this reason, this paper defines an acceleration of 3 m/s2 or more as a significant vertical car-body acceleration.
We added the reference and text in Figure 3.
"It is pointed out that if the vertical acceleration exceeds 2.8 m/s2 in the driver's cab, track maintenance should be carried out as soon as possible. For this reason, this figure defines an acceleration of 3 m/s2 or more as a significant vertical car-body acceleration.[34]"
We added following reference:
[34] Shinoda, N.;, Tsunashima, H.; Matsumoto, A.; Sato, Y.; Ogata, S.
Railway track management based on vibration data of in-service train measured by a mobile device, Japan Society of Mechanical Engineers (JSME), 2022,
https://doi.org/10.1299/transjsme.21-00375, (in Japanese).
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
the authors answered all questions and comments.
Author Response
Thank you
