High-Speed Railway
Round 1
Reviewer 1 Report
I cannot find the source material with the cited definition of High Speed Railway. According to the Author of the article, he/she had access to it in 2016, and the publication dates from 2011. The most recent definitions avoid giving specific values for train speeds. It is up to the individual countries to decide whether or not to classify a particular system as an HSR system. For example, in Poland, the HSR system includes trains running at a speed of 160 km/h. In addition, it is required to equip traction vehicles with a cab signaling system at speeds higher than 160 km/h. Therefore, it is difficult for me to agree with the above-mentioned definition of HSR from the point of view of the achievements of the railway system until 2021.
Paragraph 2 – a very modest description of the differences between conventional rail and HSR.
– section traction power: what about energy recuperation?
– section signalling system – as I mentioned in first paragraph of my review,
– section power supply – I can't agree that HSR only need 25kV voltage.
Paragraph 2 requires improvement and expansion.
Figure 3.1, 3.4, 3.10, 3.12 and 3.14 are unreadable.
Author Response
Dear Reviewer,
Many thanks for your time and effort that you took to improve my manuscript. I will do my best to respond to your comments.
- I cannot find the source material with the cited definition of High Speed Railway. According to the Author of the article, he/she had access to it in 2016, and the publication dates from 2011. The most recent definitions avoid giving specific values for train speeds. It is up to the individual countries to decide whether or not to classify a particular system as an HSR system. For example, in Poland, the HSR system includes trains running at a speed of 160 km/h. In addition, it is required to equip traction vehicles with a cab signaling system at speeds higher than 160 km/h. Therefore, it is difficult for me to agree with the above-mentioned definition of HSR from the point of view of the achievements of the railway system until 2021.
Response: I completely agree with you that there is no standard definition, because of this in the different countries there can be different values for train speed.
For example, in the USA, HSR is divided into three groups: emerging rail with speeds 145 to 177 km/h, regional rail of 177 to 241 km/h and express rail with a speed of 241km/h and above. In Japan, the railway is defined as HSR, where trains run at speed over 200km/h. There can be different restrictions for speed, such as tunnels and viaducts or highly populated areas. Some countries particular in Western Europe have old infrastructure and technology but make a huge effort to provide high speed and as in your example in Poland HSR is a railway where trains operate at speeds up to 160km/h.
However, based on European Union Directive 96/48 UIC gives the definition which I am referring to EUR-Lex - 31996L0048 - EN - EUR-Lex (europa.eu).
Jehanno, A., Palmer, D., and James, C., 2011” High Speed Rail and Sustainability”. UIC: Paris, UIC, CER. Available from www.old.uic.org/download.php/publication/531E.pdf [Accessed 04 July 2021].
The source material (above) with the cited definition of High-Speed Railway can be found on the UIC website, in Railway Technical Publications.
- Paragraph 2 – a very modest description of the differences between conventional rail and HSR.
– section traction power: what about energy recuperation?
– section signalling system – as I mentioned in first paragraph of my review,
– section power supply – I can't agree that HSR only need 25kV voltage.
Paragraph 2 requires improvement and expansion.
Response: Thank you for your comments.
In Section 2 it has been highlighted the major differences between HSR and conventional rail. The aim of this manuscript is a description of different HSR systems.
-Regarding the regenerative braking technology, it is standard in most of all new trains for HSR and conventional rail. The most energy savings shown for suburban trains and commuter trains where there are many stops during the whole line operation. For commuter trains recovery of energy is between 8-17%, for dense suburban trains around 30%. Considering HSR the recovery of braking energy largely comes when the train is entering the station, but to reduce the travel time high speed trains have fewer stops. According to some sources the energy savings of Shinkansen train series N700 in Japan equipped with regenerative braking technology, is estimated to be around 4.5% (Ctc-n.org. 2021. Regenerative braking in trains | Climate Technology Centre & Network | Tue, 11/08/2016. [online] Available at: <https://www.ctc-n.org/technologies/regenerative-braking-trains> [Accessed 9 July 2021]).
- The signalling system depends on the speed of trains. It can be from simple piece of paper given to train driver to onboard signalling system. For railway line with speed under 160km/h use trackside signals to control the safe movements of trains but if speed exceed 160km/h driver cannot reliable read signals places on trackside. So, for speed above 160km/h used onboard signalling TGVweb - The TGV Signaling System (railfaneurope.net).
In this manuscript HSR is a railway that is operated at speed above 200km/h, regarding the European Union Directive 96/48 and UIC definition EUR-Lex - 31996L0048 - EN - EUR-Lex (europa.eu).
-Power supply. In Section 2 it stated that HSR needs at least 25kV. There are three main electrification systems that are in use, and they are: 3kV DC, 15 kV AC and 25 kV AC. The lines electrified at a higher voltage have lower losses during the transformation and transmission of the energy from a power station to the train. It was found that for trains on lines electrified by 3kV DC it is necessary to produce 22.6% more than the energy received by the pantograph, for lines electrified by 25kV AC it is necessary to produce only 8% more energy than received by a pantograph. Another advantage of using 25kV AC is the possibility to supply power to high-speed trains with a greater distance between substation, which means reduction in construction and maintenance costs (A. Garcia, 2010 “High speed, energy consumption and emissions”, reference can be found at UIC, Railway Technical Publications). Yes, HSR can be powered by lower voltage, but it will increase the amount of energy that it needs produce to power high speed trains, increases the carbon dioxide emissions and increases the cost of construction and maintenance of HSR lines.
The manuscript is limited to 10,000 words so, there is no more space to extend.
- Figure 3.1, 3.4, 3.10, 3.12 and 3.14 are unreadable.
Response: Many thanks for your comments.
Figure 3.1 has been replaced by a different one.
Figure 3.4 has been altered.
Figure 3.10 has been altered.
Figure 3.12 has been replaced by a different one.
Figure 3.14 has been replaced by a different one.
Author Response File: 
Author Response.docx
Reviewer 2 Report
The aim of the article is clearly stated in the abstract. The article discusses about the High Speed Rail (HSR) technologies around the world. This article reviewed the existing HSRs and critically analysed them. The findings of the paper are interesting and have good impact in future railway operation.
The introduction section is well structured. The author has presented the aim and contribution of this article well. I consider this paper to be published after addressing the following comments.
- The table 1.1 is from 2007 and there are various new development so far. It will be good if the author update the table considering recent developments.
- Line 54: “All HSRs must have advanced signalling systems and automated train control systems.” This sentence does not clearly state the control systems used in HSRs.
- Line 80: Does all HSR use in-cab signalling system?
- Table 3.2 illustrates a good comparison of noise in HSR in Germany. Is there any equivalent numbers in case of HSRs in other countries?
- Line 629: The article did not discussed about the use of fossil fuels. However, it concluded that the HSRs can reduce the dependencies on fossil fuels. Author should conclude this with some evidence or may consider removing this sentence.
- Minor formatting issue: it will be good to use the figures wih good aspect ratio to make it readable.
Author Response
Dear Reviewer,
Many thanks for your generous comments and time and effort that you took to improve my manuscript. I will do my best to respond to your comments.
1. The table 1.1 is from 2007 and there are various new development so far. It will be good if the author update the table considering recent developments.
Response: Table 1.1 has been updated.
2. Line 54: “All HSRs must have advanced signalling systems and automated train control systems.” This sentence does not clearly state the control systems used in HSRs.
Response: Line 54 has been rewritten and expanded.
The Automated Train Control (ATC) systems was first developed in Japan and introduced for Shinkansen trains. The system was named as DS-ATC. In Europe it is European Train Control System (ETCS). The next step in developing the control systems was the introduction of ERTMS. The ERTMS system was first introduced in Italy on the 204 km line between Rome and Naples. The ERTMS combines GSM-R (communication) and ETCS (signalling) systems. With rapid progress from 2G to 5G network UIC is working on developing the successor of GSM-R, the Future Rail Mobile Communication System (FRMCS). The system can be introduced to railways as early as 2025 FRMCS and 5G for rail: challenges, achievements and opportunities (uic.org)
3. Line 80: Does all HSR use in-cab signalling system?
Response: The signalling system depends on the speed of trains. It can be in the form of a simple piece of paper given to train driver to onboard signalling systems. For a railway line with a speed under 160km/h use trackside signals to control the safe movements of trains but if speeds exceed 160km/h the driver cannot reliable read signals placed on the trackside. So, all HSRs (speeds above 160km/h) use onboard signalling.
4. Table 3.2 illustrates a good comparison of noise in HSR in Germany. Is there any equivalent numbers in case of HSRs in other countries?
Response: In different countries attitude to noise level from existing railways is different. For example, in the UK there are no legal limits to noise from existing railways Noise from roads, trains or planes: Railway noise - GOV.UK (www.gov.uk). In Japan, the limits to noise level are based on the Environment Agency standards which were introduced in 1975. The maximum noise level at 70 dB(A) for Category I (mainly residential areas and maximum level of 75dB(A) for Category II (non-Category I areas used for ordinary economic activities, such as commercial and industrial activities) (Reference N10 from manuscript).
5. Line 629: The article did not discussed about the use of fossil fuels. However, it concluded that the HSRs can reduce the dependencies on fossil fuels. Author should conclude this with some evidence or may consider removing this sentence.
Response: Due to the limitation of the manuscript to 10,000 it is not possible to extend the text. The line “It can break the dependency of the transport system on fossil fuels” has been deleted.
6. Minor formatting issue: it will be good to use the figures wih good aspect ratio to make it readable.
Response: The quality of Figures have been improved.
Reviewer 3 Report
This entry discuss about the present high-speed railway systems and their differences. The main purpose must be obviously mention in abstract (definition) and conclusion part. Overall, I think it needs some major revision.
Some comments are as follows:
1- It is not common to have reference in abstract (definition) part. It is suggested to move Ref. [1].
2-It is better to mention the article/entry purpose in definition.
3-The numbering of figures and tables are not correct. They should be like Table. 1, Figure.1, not Table 1.1 or Figure 1.1!.
4-Since the authors have already mentioned to the different HSR technologies and trains. It is better to mention different supplying voltage and frequency of systems used in each country too (1*25 kV 50/16.7 Hz, 2*25 kV, 3 kV, ... ). It is suggested to use and reference following articles in this context
doi: 10.1109/PEDSTC52094.2021.9405895
doi: 10.3390/en13246662
5- There are some typo errors, For example in line 79, it should be km/h instead of kph. Check the whole paper.
6-In table 3.3, the specification of line Firenze-Rome is missed.
7-The figure sizes and their fonts in some cases are too large, it is better to resize them.
8-In figure 3.8. and fig.3.9. remove page number and mention it in reference section. Also in lines 446 and 472.
9- line 507, km? or km/h?
10- It is suggested to mention some paragraph about future of HSR and the works which are under development regarding HSR.
For example the evolution of HSR towards MVDC system and renewables, you can use the following paper too.
doi: 10.1109/MELE.2019.2962886
Author Response
Comments and Suggestions for Authors
This entry discuss about the present high-speed railway systems and their differences. The main purpose must be obviously mention in abstract (definition) and conclusion part. Overall, I think it needs some major revision.
Dear Reviewer,
Many thanks for your valuable comments and time and effort that you took to improve my manuscript. I will do my best to respond to your comments. The purpose of this manuscript has been mentioned in the Abstract and in the Conclusions.
Some comments are as follows:
1- It is not common to have reference in abstract (definition) part. It is suggested to move Ref. [1].
Response: Reference from Abstract (Definition) has been removed.
2-It is better to mention the article/entry purpose in definition.
Response: The purpose of the Manuscript has been mentioned in the Definition.
3-The numbering of figures and tables are not correct. They should be like Table. 1, Figure.1, not Table 1.1 or Figure 1.1!.
Response: The numbering of Figures and Tables have been changed.
4-Since the authors have already mentioned to the different HSR technologies and trains. It is better to mention different supplying voltage and frequency of systems used in each country too (1*25 kV 50/16.7 Hz, 2*25 kV, 3 kV, ... ). It is suggested to use and reference following articles in this context
doi: 10.1109/PEDSTC52094.2021.9405895
doi: 10.3390/en13246662
Response: There has been added information about different electrification systems. Due to limitation of Manuscript to 10,000 only the following information has been added.
There are three main electrification systems that are in use, and they are: 3kV DC, 15 kV AC and 25 kV AC. The lines electrified at a higher voltage have lower losses during the transformation and transmission of the energy from power station to the train. It was found that for trains on lines electrified by 3kV DC it is necessary to produce 22.6% more than the energy received by the pantograph, for lines electrified by 25kV AC it is necessary to produce only 8% more energy than received by a pantograph. Another advantage of using 25kV AC is the possibility to supply power to high-speed trains with a greater distance between substation, which means reduction in construction and maintenance costs (A. Garcia, 2010 “High speed, energy consumption and emissions”, reference can be found at UIC, Railway Technical Publications). HSR can be powered by lower voltage, but it will increase the amount of energy that it needs produce to power high speed trains, increase the carbon dioxide emission and increase the cost of construction and maintenance of HSR lines.
5- There are some typo errors, For example in line 79, it should be km/h instead of kph. Check the whole paper.
Response: Line 79 has been corrected, and the paper has been checked again.
6-In table 3.3, the specification of line Firenze-Rome is missed.
Response: Regarding Table 3.3 the author does not have information about Firenze-Rome line. The Table 3.3 is only an example of construction costs of some of the selected HSR lines in Italy.
7-The figure sizes and their fonts in some cases are too large, it is better to resize them.
Response: The quality of Figures have been improved.
8-In figure 3.8. and fig.3.9. remove page number and mention it in reference section. Also in lines 446 and 472.
Response: The Figure 3.8 and 3.9 and in the lines 446 and 472 the number of pages has been removed and mentioned in the reference section.
9- line 507, km? or km/h?
Response: Line 507 has been corrected.
10- It is suggested to mention some paragraph about future of HSR and the works which are under development regarding HSR.
Response: In the Conclusions it has been mentioned HSR projects that are under construction or planning to be constructed. Due to the limits of the current paper to 10,000 it was impossible to write in more detail.
For example the evolution of HSR towards MVDC system and renewables, you can use the following paper too.
doi: 10.1109/MELE.2019.2962886
Response: The MVDC-ERS has been mentioned as one of the technical solutions that can increase efficiency of the power distribution and support to consolidate the renewable energy sources. The paper doi: 10.1109/MELE.2019.2962886 has been added to the reference list.
Round 2
Reviewer 1 Report
I am very pleased that the Author took my comments into account. Now we have the encyclopedic dimension of the HSR article. Congratulations.
Reviewer 2 Report
The author has addressed all the comments made by the reviewers. The modified manuscript is now recommended to publish in its current form.
Reviewer 3 Report
The author have responded to my answers (Thank you). However, I think still paper has some typo errors. It is better to check them before publication.
