Dear authors,

many thanks for your revised version and answers to the reports of the two reviewers. Due to the nature of the major comments of one of the reviewers, the manuscript was again sent out for review. This second review highlighted once more the two main concerns that still remain, also from my point of view:

(1) There are still (and even more so after your revision) some serious problems with the english language. Whereas the main part of the original manuscript can be well understood, this is not the case for most of your revision and also your answers to the reviewers comments. Sometimes it is not possible to understand at all what you want to say, e.g. the new lines in the abstract; also the lines 1-3 on page 6; and as well the new text on pages 11 and 12. Without an improvement of the english of the whole manuscript, at least to a point where the meaning of all sentences can be understood, the manuscript cannot be published. After this improvement, we can provide help for the final polishing of the english.

(2) In the original review the reviewer has formulated several questions that should be addressed in the manuscript: "What happens to the insulating vegetation layer when it is buried under the railroad grade? How thick is this vegetation layer, and how would the heat transfer through this layer interact with the heat transfer through the railroad grade/road bed during different times of the year? How would lateral heat transfer play a role? Could the different geometries of the roadbed/the railroad grade play a role? Is it certain that winter snow cover can entirely be neglected in the discussion (the authors state that there is no steady or winter-long snow cover)? Is there snow accumulation at the shoulders of the road/railroad? What causes the significant offset between MAAT and MAGT (Table 2) if it is not snow? Is this related to radiative heating of the surface and thereby caused difference between MAAT and MAGST?"

Although it is clear that most of these questions cannot be definitely answered within the present study (as you pointed out in your answer), their relative importance and/or their potential impact on the uncertainty of the results of your study can be discussed. These uncertainties should at least be mentioned, and their effect may be estimated using results from other studies. The reviewer suggested to include a discussion on the possible magnitude of each effect, e.g. how much additional heating and thus difference between MAAT and MAGST can one expect from radiative heating on an asphalt surface? Are there numbers for this effect on the Qinghai-Tibet Plateau presented in other publications? Furthermore, the author’s response on the effect of highway/railroad geometries could be included in the manuscript, including references to the relevant studies.

Minor comments:
- P6, l. 11: 2cm/a
- reference Zhao et al. 2004 (page 5) is missing in the reference list.

Both, the reviewer and myself feel that your revisions already made the paper scientifically much stronger, but the poor english of the revisions are prohibiting any publication at the moment.

With my very best regards,
Christian Hauck

Dear authors,

thank you very much for your extensive revisions, which greatly improved the readability and also the scientific content of your paper. We now think that your paper is ready for publication under the condition that a series of small corrections (mostly language related) are conducted. I re-read the entire manuscript and made propositions for language changes in the attached document (please consult the full list of changes/comments). Please verify carefully whether the proposed changes are still conform with your intended meaning of the respective sentences.

After this minor revision step, the paper is ready to be published in TC.
With my best regards,

Christian Hauck

Dear authors,

many thanks for your revised version. I found the following technical corrections to be done:

page 2, line 6: "Climate warming has varying thermal impacts on permafrost in different alpine ecosystems (Wu et al., 2015), change in permafrost temperature and active layer thickness (ALT) of alpine meadows is greater than that of alpine steppe (Wu et al.,
2015)."
--> should be changed to:
"Climate warming has varying thermal impacts on permafrost in different alpine ecosystems (Wu et al., 2015). For example, the change in permafrost temperature and active layer thickness (ALT) of alpine meadows is greater than that of alpine steppe (Wu et al., 2015)."

page 5, line 16: "to result below natural surfaces" --> "results" instead of "result"

page 12, line 1: "but whereas" --> should be "whereas"

page 12, line 7: "that that vegetation" --> should be "that the vegetation"

page 13, line 4: "within long-term" --> should be "in the long-term"

page 13, line 28: a bracket ( is missng here: "are generally small, (< 1 °C and
20 cm, respectively, Wu et al., 2011),"

page 14, line 5: "and a short snow cover duration of cover" --> should be "and a short snow cover duration"

with my best regards,
Christian Hauck