【正文】 o referees made valuable ments and suggestions on the revised version of the paper resubmitted on 28 April, 2021. We appreciate very much their helps and encouragements. All ments and suggestions have been considered in this round revision. This report list our responses in detail. For the sake of presentation, the ments of the referees are numbered and duplicated in italics, our responses are given in plain. Responses to the ments made by the first referee Comment (1) The authors suggest on p. 3, ……………… . Standingup is a mon feature of riding on metro systems in very large cities. The authors do not adequately describe this feature at the beginning of the first paragraph on p. 3. Responses Thanks very much for this criticism and advice. According to the referee’s suggestion, we have improved ………… .. Comment (4) This asymmetrical crowding effect is very different from the congestion in road traffic in which the congestion is virtually equally shared by all vehicles on the road, irrespective of their origins. Therefore, one cannot directly transplant the theories in road traffic, such as the use of Beckmann transformation in Eq.(5), to transit modeling. Noheless, the reviewer is quite confident that this problem can surely be handled by the talented authors in their revised version of the mathematical model. Some other ments are given as follows. Responses We agree this viewpoint that the crowding effect in transit problem is quite different from that in road traffic. In fact, this is reflected by the construction of Eq. (2), ., the invehicle crowding cost function in which the crowding effect is increasingly accumulative from upstream stations to downstream. In modeling the case with seat consideration, priority should be given to upstream passengers, see subsection . Comment (5) At the end of the second line in the abstract, delete the repeated phrase “in a”. In line 11 on page 2, should it be “seminal” work? In line 19 on the same page, change the “in a urban area” to “in an urban area”. Responses Thanks. We have corrected and revised in the new version. Comment (11) In line 11 on page 7, change “thy” to “they”. Responses Thanks. We feel shame at having so many ? Comment (1) This paper provides an interesting mathematical study of the equilibrium properties of muters in a mass transit system with many origins and a single destination during the morning rush hour. The claimed theorems are elegantly proven. The mathematics is reliable as far as the reviewer can see. However, there is a fundamental flaw in the modeling assumption for transit services that seemingly leads to some counterintuitive results, which may not truly reflect the realistic situation. The authors need to rectify this problem in their mathematical model, before the paper can be considered for publication in Transportation Research Part B. This major criticism lies in the asymmetric property of transit service…... ? Responses Thanks very much for this criticism. In the revised version, we highlight such a phenomenon observed in Beijing “According to our observation in Beijing’s mass transit system, ….” In addition, for considering the asymmetric property of transit service, we extend the model to the case with constraint on the number of seats, please see subsection in the revised version. We found that the equilibrium departure time distribution still exists and there is a watershed for stations along the corridor. Commuters boarding trains at upstream stations of the watershed have seats in train vehicles, while those boarding trains at downstream station of the watershed have to be standup. As an example of studying the case with seats, we present and prove an equivalent minimization problem when the watershed station is the first station. The third example confirms the result by the equivalent minimization problem. 正確對待和處理退稿 ?要正常心態(tài)，好刊物都只有 1020%的錄用率，退稿是正常的，原因是多方面的（確實稿件貢獻不夠、質(zhì)量太低，也可能是論文太超前、審稿人不識貨） ?退稿不要不加修改就改投其它刊物，否則往往再次遭受挫折，還會損害聲譽（浪費審稿專家的時間，在同行里留下不好影響） ?必須是仔細修改、擴充后，再等一段時間投出去。 電學之父 —法拉第 (Michael Faraday， 17911867)： The secret is prised in three words — Work, finish, publish. His wellknown advice to the young William Crookes, who had asked him the secret of his success as a scientific investigator, as quoted in Michael Faraday (1874) by John Hall Gladstone, p. 123 發(fā)表論文的重要性 結 語 ? 科學研究的本性是 對未知的探索、以求明理。北朝 齊 (479502) 顏氏推 《 顏氏家訓 勉學 》 ：讀書學問，本欲開心 明目 。 ? 科學研究的過程中，真理與謬誤的共存，要撥開迷霧，知難而進，堅忍不拔，從善如流。 興趣 ＋持之以恒 謝 謝！ （部分素材取自公開網(wǎng)站，特此鳴謝）