彭納

成都，拉薩，一個(gè)地處四川盆地，一個(gè)位于世界屋脊，地圖上直線距離顯示為1250公里。從萬(wàn)米高空向下俯瞰，層巒疊嶂的山峰、奔騰呼嘯的大江像無(wú)形之手刻下的道道溝壑，將兩地遠(yuǎn)遠(yuǎn)隔開(kāi)。如今，一條全長(zhǎng)1572千米的鐵路，將翻越大自然設(shè)下的屏障，跨過(guò)奔流千年的江河，從海拔500米的成都平原，歷經(jīng)“八起八伏”，累計(jì)爬升14000多米，一路盤(pán)亙到達(dá)海拔4000多米的青藏高原。

我深深感到，在西南復(fù)雜山區(qū)誕生一條鐵路是何其艱難。但是，從沒(méi)有一條鐵路像這條，令人望而生畏卻又熱情高漲……”令中鐵二院副總工程師林世金感慨萬(wàn)千的正是修建中的川藏鐵路。

2018年10月10日，習(xí)近平總書(shū)記主持召開(kāi)中央財(cái)經(jīng)委員會(huì)第三次會(huì)議，全面啟動(dòng)川藏鐵路規(guī)劃建設(shè)工作。作為五條進(jìn)藏鐵路之一的川藏鐵路，分為成雅鐵路（成都—雅安）雅林鐵路（雅安—林芝）、拉林鐵路（拉薩—林芝）三段。據(jù)悉，2014年底成雅段和拉林段兩頭開(kāi)工，其中成雅鐵路在2018年底已建成通車(chē)，拉林段桑珠嶺隧道已于2018年1月17日正式貫通。三段當(dāng)中，里程最長(zhǎng)、施工難度最大的雅林段，在2018年底破土動(dòng)工，修建時(shí)長(zhǎng)為10年左右，預(yù)計(jì)2030年該路段通車(chē)后，川藏鐵路將實(shí)現(xiàn)全線貫通。

二一十年磨一劍

從西部交通運(yùn)輸網(wǎng)絡(luò)的分布來(lái)看，多年來(lái)，連通四川和西藏的除了探險(xiǎn)者青睞的川藏公路外，只有一趟成都開(kāi)往拉薩的旅客列車(chē)，列車(chē)從成都出發(fā)，途徑蘭渝鐵路至蘭州、經(jīng)西寧、德令哈、格爾木、那曲，最終抵達(dá)拉薩，單邊耗時(shí)30多個(gè)小時(shí)。由于運(yùn)行線路長(zhǎng)、客流少等原因，這趟列車(chē)一直都是隔日發(fā)車(chē)。因此，川藏鐵路的修建在當(dāng)下意義重大。

早在上世紀(jì)50年代，中鐵二院就已踏上“征途”，開(kāi)始對(duì)進(jìn)藏鐵路進(jìn)行研究，多次赴沿線考察踏勘的專(zhuān)家們，成為了川藏鐵路最初的拓荒者。但因建設(shè)難度大、科技要求高，計(jì)劃暫時(shí)被擱置。

中國(guó)科協(xié)副主席、中國(guó)鐵路總公司總工程師、中國(guó)工程院院士何華武曾在川藏鐵路建設(shè)難度學(xué)術(shù)交流會(huì)上道出了川藏鐵路的建設(shè)難點(diǎn)，“川藏線途經(jīng)多個(gè)差異巨大的地貌單元，以及高地震烈度區(qū)、山地災(zāi)害頻發(fā)區(qū)等災(zāi)害集中區(qū)，選線選址需同時(shí)解決地形、地質(zhì)、氣候等綜合性問(wèn)題。”

當(dāng)中鐵二院拓荒者們的身影再次行進(jìn)在西南群山中時(shí)，已經(jīng)是2008年，這一年，新一輪的川藏鐵路建設(shè)啟動(dòng)。中鐵二院主管川藏鐵路勘察設(shè)計(jì)工作的副總工程師林世金和整個(gè)團(tuán)隊(duì)興奮地踏上了前人走過(guò)的路。

王筑是中鐵二院的測(cè)量工人，跟隨踏勘團(tuán)隊(duì)，在一個(gè)隆冬的上午來(lái)到了安拉隧道完成放線工作，隧道進(jìn)口海拔3300米，頂線海拔4300米，由于缺氧，每爬十來(lái)米王筑就要停下來(lái)歇一歇，當(dāng)測(cè)量工作完成時(shí)，太陽(yáng)已經(jīng)快下山了?！吧仙诫y下山更難?！蓖踔吇貞涍呎f(shuō)道，當(dāng)時(shí)，身旁?xún)蓚?cè)一邊是望不到頂?shù)难┓?，一邊是深不可測(cè)的峽谷，王筑只能將儀器綁在胸前，半躺在雪地上手腳并用地往下挪。

正如林世金所說(shuō)，這條線路雖然令人望而生畏，卻又有讓大家熱情高漲的魔力。

一次在西藏昌都，看著從勘察現(xiàn)場(chǎng)顛簸到半夜才回駐地的工程師們滿(mǎn)身泥濘地從車(chē)上下來(lái)，當(dāng)?shù)卣ぷ魅藛T忍不住感慨：“現(xiàn)在連我們當(dāng)?shù)厝硕疾桓疫M(jìn)的深山你們進(jìn)去了，連牦牛都不愿上去的荒嶺你們也上去了。

當(dāng)林世金和團(tuán)隊(duì)一頭扎進(jìn)大自然的壯闊之中時(shí)，他們對(duì)“鬼斧神工”四個(gè)字也有了別樣的理解。由于川藏鐵路要穿越印度板塊和歐亞板塊的碰撞縫合帶，線路在經(jīng)過(guò)變化多端的地形、地貌的同時(shí)，常常伴隨著地震、滑坡、崩坍、泥石流、冰湖潰決等地質(zhì)災(zāi)害。而線路在橫跨大渡河后，馬上進(jìn)入折多山區(qū)，山河之間的航空距離只有51公里，但鐵路卻要面臨陡然爬升2500米巨大高差的難題……如此種種，都是橫亙?cè)诮ㄔO(shè)者們面前的一道道“超級(jí)難關(guān)”。

巨型過(guò)山車(chē)背后的“超級(jí)難題”

和青藏鐵路“緩坡式”上升不同，川藏鐵路呈“臺(tái)階式”，上升模式。高低落差之大，工程師們形象地稱(chēng)其為“巨型過(guò)山車(chē)”，要完成這項(xiàng)世界上技術(shù)難度最大的超級(jí)工程，也必須解決好其帶來(lái)的“超級(jí)難題"。

面對(duì)四川、西藏多樣的地形、地貌以及惡劣的氣候環(huán)境，如何選擇一條優(yōu)質(zhì)的路線是擺在工程師面前的一道難題。

談起這個(gè)問(wèn)題，林世金舉了一個(gè)例子，線路需要穿越橫斷山脈，那么這條線應(yīng)該怎么走？三個(gè)方案擺在了討論桌前，第一是經(jīng)理塘一昌都，第二是經(jīng)甘孜一昌都，第三則是沿318國(guó)道修建。經(jīng)甘孜、昌都方案又提出了經(jīng)道孚、經(jīng)新龍兩個(gè)子方案。綜合比較了地形地質(zhì)、分析"了各種優(yōu)劣，考慮經(jīng)濟(jì)據(jù)點(diǎn)、綜合交通，經(jīng)過(guò)反復(fù)討論，最終第一方案入選。而在設(shè)計(jì)桑8至加查段時(shí)，工程師們采取了沿雅魯藏布江走的保守設(shè)計(jì)方案，但當(dāng)實(shí)地勘測(cè)時(shí)，大家發(fā)現(xiàn)，沿江兩岸全是嚴(yán)重的危巖落石，工程地質(zhì)條件極差，3000多米高差的峽谷，就算一塊雞蛋大的石頭滾下來(lái)打到列車(chē)上，后果也不堪設(shè)想，經(jīng)過(guò)反復(fù)琢磨，兩跨雅魯藏布江的方案誕生，這一優(yōu)化，為國(guó)家節(jié)省投資1億零61萬(wàn)元。而且由于線路縮短了1.84公里，通車(chē)后，每年還將繼續(xù)節(jié)約200萬(wàn)元以上的運(yùn)營(yíng)費(fèi)用。

從成都到拉薩，川藏鐵路需要跨越四川盆地、青藏高原，而中國(guó)最長(zhǎng)、最寬和最典型的南北向山系一橫斷山脈橫臥其間，各條山脈之間，鑲嵌著大渡河、鮮水河、雅礱江、金沙江、瀾滄江、怒江等河谷，組成了嶺谷相間、山重水復(fù)的巨大山原，嶺谷之間的高差達(dá)兩三千米。為消除這種高差地形帶來(lái)的影響，川藏鐵路大量采用高橋、隧道設(shè)計(jì)，據(jù)悉，全線橋隧比達(dá)92.9%。在面對(duì)短距離高落差的難題時(shí)，設(shè)計(jì)師們采用了大坡度、高橋長(zhǎng)隧的方式來(lái)解決，將來(lái)鐵路通車(chē)后，乘客們可以在76公里的路段明顯感覺(jué)到大坡度的攀爬軌跡，這也是目前國(guó)內(nèi)最長(zhǎng)的坡度地段。

伴隨以，上問(wèn)題的還有板塊強(qiáng)烈碰撞擠壓抬升引發(fā)的強(qiáng)烈地震;平均海拔4000米左右，因積雪融化產(chǎn)生的崩坍、冰湖潰決、巖爆、風(fēng)積沙、泥石流、峽谷風(fēng)、季節(jié)性?xún)鐾恋葐?wèn)題，據(jù)悉，與鐵路規(guī)劃同步開(kāi)展的，還有50多項(xiàng)“減災(zāi)選線”的研究。中鐵二院總經(jīng)理朱穎認(rèn)為，山區(qū)鐵路選線技術(shù)已經(jīng)從地形地質(zhì)選線發(fā)展到減災(zāi)選線階段，川藏鐵路正是遵循了復(fù)雜艱險(xiǎn)山區(qū)鐵路減災(zāi)選線的理論和技術(shù)。

經(jīng)過(guò)3年多奮戰(zhàn)，2018年1月178川藏鐵路拉林段桑珠嶺隧道貫通。據(jù)中鐵五局桑珠嶺隧道項(xiàng)目負(fù)責(zé)人朱胥仁介紹，隧道修建中，對(duì)施工作業(yè)環(huán)境影響最大的當(dāng)屬超高地溫。在這里，巖溫最高達(dá)到了89.9°C，隧道內(nèi)的溫度最高達(dá)到'了56°C。而對(duì)隧道施工風(fēng)險(xiǎn)最大的則是巖爆，巖爆發(fā)生時(shí)伴隨巖塊彈射、拋射現(xiàn)象，巖塊彈射最大距離達(dá)25米，威力堪比槍械。正是得益于對(duì)“減災(zāi)選線”的扎實(shí)研究，在雅林段的設(shè)計(jì)中，線路盡可能減少了隧道高地溫、強(qiáng)巖爆、大變形等一系列施工難題。

13小時(shí)以外的意義

總投資約3000億，設(shè)計(jì)速度200km/h，部分路段限速160km/h，川藏鐵路從天府之國(guó)成都始發(fā)，經(jīng)蒲江、雅安、理塘、昌都、林芝、山南，13小時(shí)后駛抵西藏首府拉薩。這條云端“天路”通車(chē)帶來(lái)的意義，絕不僅僅是提速20個(gè)小時(shí)這么簡(jiǎn)單。

在2015年西藏自治區(qū)十屆人大三次會(huì)議上，西藏確立了對(duì)接“一帶一路”和孟中印緬經(jīng)濟(jì)走廊，推動(dòng)環(huán)喜馬拉雅經(jīng)濟(jì)合作帶建設(shè)，構(gòu)建對(duì)內(nèi)對(duì)外開(kāi)放型經(jīng)濟(jì)新格局的發(fā)展理念。據(jù)悉，環(huán)喜馬拉雅經(jīng)濟(jì)合作帶以樟木、吉隆、普蘭0岸為窗口，以拉薩、8喀則等城市為腹地支撐，面向尼泊爾、印度、不丹，發(fā)展邊境貿(mào)易、國(guó)際旅游、藏藥產(chǎn)業(yè)以及特色農(nóng)牧業(yè)、文化產(chǎn)業(yè)等。西藏自治區(qū)社科院經(jīng)濟(jì)戰(zhàn)略研究所所長(zhǎng)王代遠(yuǎn)表示，經(jīng)濟(jì)合作帶的打造，將為西藏的發(fā)展帶來(lái)前所未有的機(jī)遇。抓住此契機(jī)，西藏將實(shí)現(xiàn)交通、貿(mào)易、金融、能源和現(xiàn)代物流業(yè)等領(lǐng)域的升級(jí)，促進(jìn)社會(huì)經(jīng)濟(jì)的快速發(fā)展。

川藏鐵路的通車(chē)無(wú)疑將為這一發(fā)展理念注入強(qiáng)大動(dòng)力。此外，川藏鐵路的修建，還將打通中國(guó)長(zhǎng)江經(jīng)濟(jì)帶與南亞陸路經(jīng)貿(mào)通道。屆時(shí)，中國(guó)華中、華東、華南地區(qū)通往南亞的陸路通道有望因此形成。

王代遠(yuǎn)還談到，從長(zhǎng)遠(yuǎn)來(lái)看，修建川藏鐵路對(duì)于促進(jìn)西藏東部融入成渝經(jīng)濟(jì)圈，加強(qiáng)西藏與四川在傳統(tǒng)合作的層次上提高到更高的等級(jí)具有重要作用。作為交通大動(dòng)脈，鐵路是現(xiàn)代交通最重要的類(lèi)型，只有形成網(wǎng)絡(luò)才會(huì)發(fā)揮更大的經(jīng)濟(jì)效益。青藏鐵路的通車(chē)改變了西藏不通鐵路的歷史，填補(bǔ)了其鐵路交通上的空白，對(duì)經(jīng)濟(jì)的促進(jìn)作用已經(jīng)初步呈現(xiàn)。當(dāng)川藏鐵路與青藏鐵路形成環(huán)線后，這種促進(jìn)作用將更加明顯。

據(jù)估算，未來(lái)川藏鐵路直接吸引范圍面積約為52萬(wàn)平方公里，人口約2360萬(wàn)。此外，還將輻射相鄰旅游區(qū)的建設(shè)，比如川西南、滇西北等。在川藏鐵路的輻射下，馬爾康卓克基土司官寨、有4000多年歷史的昌都卡若遺址;雪山、草原等自然生態(tài)景觀，藏著巨大的資源開(kāi)發(fā)和經(jīng)濟(jì)發(fā)展?jié)摿?，這些當(dāng)初因?yàn)榻煌l件限制發(fā)展的問(wèn)題將在未來(lái)得以解決?！伴L(zhǎng)期以來(lái)，交通一直是制約西藏經(jīng)濟(jì)發(fā)展的瓶頸，雖然目前有所緩解，但是仍然存在很大的限制。川藏鐵路建成后，將建立一個(gè)快捷的大容量通道，大量的游客將通過(guò)川藏鐵路到達(dá)拉薩，這就把區(qū)外的消費(fèi)轉(zhuǎn)變?yōu)閰^(qū)內(nèi)消費(fèi)，進(jìn)一步帶動(dòng)西藏旅游業(yè)的增長(zhǎng)?！蓖醮h(yuǎn)分析道。

在拉薩開(kāi)川菜館的王老板聽(tīng)說(shuō)川藏鐵路全面開(kāi)工后激動(dòng)不已，“聽(tīng)說(shuō)川藏鐵路通車(chē)后，從拉薩乘火車(chē)十幾個(gè)小時(shí)就到成都了，我和老婆都高興得很。每年回成都過(guò)年，我們都要坐差不多兩天的火車(chē)，非常難熬，以后我們?cè)缟铣霭l(fā)，下午就可以到家了。

川藏鐵路，這條歷時(shí)幾十年的超級(jí)工程，承載了太多人的心血與汗水，也承載了太多人的期許與渴望。我們期盼著，2030年左右，這條鋼鐵巨龍?jiān)谌荷綔羡种邢蛑h(yuǎn)方飛躍、飛躍……

規(guī)劃建設(shè)川藏鐵路，對(duì)國(guó)家長(zhǎng)治久安和西藏經(jīng)濟(jì)社會(huì)發(fā)展具有重大而深遠(yuǎn)的意義，一定把這件大事辦成辦好！

——習(xí)近平

Planning and building the Sichuan -Tibet Railway is of profound significance for the country’s long-term stability and the economic and social development of Tibet. Hence， the project must be?processed well.

——General Secretary Xi Jinping

How long is 1，250 kilometers?Lon the map？ Just imagine a?trek from Chengdu， a low- -lying city inSichuan Basin to Lhasa， a high-lying city?on the Tibetan Plateau， the “Roof?of the World". Looking down from a?height towering about 10，000 meters，?views are a constant source of rolling lofty?mountains and billowing mighty?rivers which have left the two cities far apart?like one after another deep ravine carved?by an invisible hand. Now， a1572 kilometer long railway will startfrom 500-meter-high Chengdu Plain，?and climb onto over-4，000-meter-high Tibetan Plateau. Over the course，?it will negotiate myriad natural barriers and?surging rivers with "eight ascents and?descents"， and the accumulated height?it will climb reaches more than14，000 meters.

"I could deeply feel ho Extremely?hard building a railway across?geographically complicated southwestern?mountainous areas would?be. However， never a railway like?it has left us tor between deepfear and great enthusiasm..." Lin?Shijin， deputy chief engineer of ChinaRailway Eryn an Engineering GroupCo.， Ltd.（CREEC）， said with emotion at?the mention of Sichuan- Tibet Railway currently?under construction.

On October 10， 2018， GeneralSecretary Xi Jinping presided over the?third meeting of the CentralCommittee for Financial and EconomicAffairs， marking the all-round efforts in?materializing the construction plan?for the Sichuan- Tibet Railway. As one?of China's five railways to Tibet， theSichuan- Tibet Railway consists of?three segments， namely Chengdu-Ya'an railway， Ya'an- Nyingchi railway?and Nyingchi-Lhasa railway. According?to reports， construction of Chengdu-Ya'an railway and Nyingchi-Lhasa?railway started in late 2014， advancing the?project from both ends. Some headway?has been made respectively- Chengdu-Ya'an railway started operating?in late 2018 and Sangzhuling?tunnel began to be operated onJanuary 17， 2018. Significantly， Ya'an-Nyingchi railway- the most difficult?and longest segment -broke ground in?late 2018， and is scheduled to be finished?by 2030. In other words， theSichuan-Tibet Railway will open to traffic?about ten years later.

Twenty years of devotion makes a?railway legend happen

West China's transportation network?branches from Chengdu toLhasa with only one passenger train，?complemented by the Sichuan-TibetHighway which is often preferred byTibet-bound adventurers. Startingfrom Chengdu， making a detour at?Lanzhou via Chongqing-Lanzhou Railway， passing by Xining， Delingha，?Golmud and Nagqu and enteringLhasa， this only train takes travelers as?long as over thirty hours for a one-way trip. In addition， due to the long journey?time and low throughput， it?has been operating every other day since?opening to traffic. Therefore，?building the Sichuan-Tibet Railway is?of great significance to meet short-term needs.

As early as the 1950s， CREEC has embarked?on a "trek"- for years?，its experts have conducted many?theoretic studies and field trips onTibet-bound railways， making them?the first pioneers of the Sichuan-TibetRailway. Yet， a high degree of difficulty and?a high demand on technological?sophistication have shelved its construction plan.

"The Sichuan-Tibet Railway runs through?not only many distinct-geomorphic?units， but also disaster areas?like high earthquake intensity areas?and areas vulnerable to mountain?hazards， so many aspects like topography， geology and climate should be?taken into consideration as a whole in?deciding on its route and location，"said He Huawu， vice chairman ofChina Association for Science andTechnology， chief engineer of ChinaRailway and academician of ChineseAcademy of Engineering， at the academic?seminar of "Challenges andStrategies in Sichuan-Tibet RailwayConstruction".

It was until 2008 that CREEC’ Spinners?embarked on a field trip?again to mountain ranges inChina's southwest. This year has witnessed?the launch of a new round of?construction works of the Sichuan-Tibet Railway. Hence， Lin Shijin， the then?deputy chief engineer of CREEC?in charge of survey and design work?of the Sichuan-Tibet Railway， led his?team to follow the beaten track blazed?by his predecessors with great enthusiasm.

One morning in the depths of?winter， CREEC's surveyor Wang Zhu?together with the field survey team came?to Anla Tunnel to complete the setting?out work. As the tunnel is 3，300meters high at the mouth and 4，300meters high at the top line， Wang Zhu?had to stop climbing for a break every ten?or so meters because of hypoxia.When he completed the survey work，?the sun was already about to set. "Itis more difficult to go downhill than?to climb uphill，" recalled Wang Zhu.At that time， the tunnel was flanked by?endlessly high snow peaks and-bottomlessly?deep gorges， so he had?to half lie on the snow-covered ground and?inch down on all fours， with the instruments?fastened to his chest.

Just as engineer Lin said， thought his?route is very daunting， it has cast as?pell to keep the team in high spirits.

One day at Qamdo， Tibet， a?group of engineers returned to their encampment?from field survey in the midnight， their bodies covered in mud.Seeing that， even local officials cannot help?exclaiming， “ Now， you haveleft your footprints in the depths of mountains?that daunt our locals and the deserted?ridges that disgust our yaks."

When Lin and his team devoted themselves?to exploring the splendidnature， "superlative craftsmanship" was getting?to them differently. Because the?railway has to traverse the collision and?suture zones between Indian andEurasian plates， the route is bound to?run through regions accompanied by?all kinds of geological disasters due to sharp?changes in terrain and landform?，like earthquake， landslide， collapse?，debris flow and glacial lake outburst.Significantly， it is all the more so in?the case of section that runs through?Dadu River and Zheduo Mountain.Despite a flying distance as short as 51kilometers between the two spots， the railway?has to wind upwards as high as2，500 meters ...

Super difficulties behind building the?"giant roller coaster"

Unlike the Qinghai-Tibet Railway?that is routed along a gentle slope， theSichuan-Tibet Railway indeed mounts many?"stairs". With a sharp drop height， engineers aptly described it asa "giant roller coaster". To complete this?world's most technically difficult project， a succession of accompanying"super difficulties" must be risen above.

Given the diversity in terrain and?land form as well as the bad weather of?Sichuan and Tibet， how to plan a quality?route is quite a nut to crack forengineers.

At the mention of this problem，Lin expounded by taking an example?like the section needs to run through?Hengduan Mountains， the best?alliterative?route has become a tough choice. At that time， three alternativeswere put on the table-- Litang?County-Qamdo City， Garze County-Qamdo City and a route along China?National Highway 318. In particular， for?Garze County- -Qamdo City alternative?，two detailed options， Garze County-Dawu County-Qamdo City and?Garze County - Nyarong County-Qamdo City， were put forward.Based on a comparative analysis?of advantages and disadvantages in?terrain and geography， and a comprehensive?analysis of economy and?transportation， the first alliterative was chosen after repeated discussion.When designing the Sangri-GyacaCounty section， engineers decided on following?the conservative route alongYarlung Zangbo River at first. But， after field?trips， they found that the river is?lined by many dangerous and fallenrocks， leading to the poor engineeringgeological condition; the canyon nearby?has a drop height of more than3，000 meters， which means even if?an egg-sized rock fell on the train，?it would have dire consequences.For that reason， the plan of crossingYarlung Zangbo River twice was developed?after careful deliberation.In addition， the improvement plan has?cut down investment by RMB100.61 million Meanwhile， as the line is?shortened by 1.84 kilometers， morethan RMB 2 million of operational costs?will be saved annually once thetrain opens to traffic.

Starting from Chengdu to Lhasa，?the Sichuan-Tibet Railway needs?to traverse Sichuan Basin， TibetanPlateau， and in particular Hengduan?Mountains， China's longest， widestand most typical north-south mountain range. With Dadu River，?Xianshui River， Yalong River， JinshaRiver， Lancang River， Nujiang Riverand other river valleys sandwiched between?the mountains， there lies a?vast mountain plateau featuring a crisscross?pattern of ridges， valleys?，mountains and rivers with a drop height?of two or three thousand kilometers?from ridges to valleys.To eliminate the effect of significant terrain?elevation differences， the railway?designers have turned to a?heavy use of high bridges and tunnels.According to reports， about 92.9%length of the alignment will be tunnelsand bridges. Faced with a drastic drop?height over a short distance，?designers took advantage of the “great gradient， high bridges and long tunnels"method to overcome the difficulty.In the future after the railway opens，?travelers can experience a noticeable steep?climb trajectory when the train runs?across the sections with a speed?of 76 km/h. The longest gradient section?in China is achieved in the construction?of the railway.

In addition to the design gradient，?the sharp drop height also brings about?other difficulties， such as strong?earthquakes caused by drastic collision， extrusion and lifting between plates， devastating collapse and bursts caused?by melting ice and snow in?regions with an altitude of about?4，000 meters， and other problems likeglacial lake outburst， rock burst，?aeolians and， debris flow， canyon wind and seasonal?frozen soil. According to relevant?reports， over 50 scientific studies?on "disaster prevention and route?selection"， therefore， have been conducted?in tandem with the planningwork for the railway. Zhu Ying，?CREEC's general manager， held that?as technologies for railway alignment in?mountainous regions has shifted focus?from topography and geology to?disaster prevention， the Sichuan-Tibet Railway has been routed based?on the disaster-prevention-focused alignment technology and theory?for complicated and dangerous mountainous regions.

Thanks to more than three years?of hard work， Sangzhuling Tunnelin Nyingchi-L?has?a section was completed?on January 17， 2018.According to Zhu Xuren， head of?Sangzhuling Tunnel project of ChinaRailway No.5 Engineering GroupCo.， Ltd.， during constructing the tunnel， the biggest affecting factor for?the construction environment is?the super high terrestrial heat. Here，?the temperature of rocks and inside?the tunnel reaches 89.9 °C and 56 °Respectively?at the highest. Yet， the biggest?danger for tunnel construction is?the rock burst， for it is always accompanied?by rock catapulting and casting. With a farthest range of 25meters， rock catapulting has the force?that matches weapons. Therefore，?if it were not for the solid studies on?"disaster- prevention-focus?dealignment"， the tunnel construction should?not have reduced a series of?difficulties like high terrestrial heat， strong rock burst and serious deformation?in designing Ya' an-Nyingchi Section.

Significance beyond the 13-hours travel?time

With a total investment of aboutRMB 300 billion?and a design speed of200km/h （160km/h in some sections），the Sichuan-Tibet Railway starts fromChengdu， passes by Pujiang， Ya'an，Litang， Qamdo， Nyingchi and Shannan，?and enters Tibet's capital Lhasa with a?travel time of 13 hours. However， once opening?to traffic， this cloud-kissing"sky road" will benefit the regions along it?in many ways， definitely much morethan cutting the travel time by twenty hours.

At the Third Session of the 10thPeople's Congress of the PartyCommittee and Government of TibetAutonomous Region in 2015， Tibet articulated?the development concept of?forming a new economic pattern featuring?inward and outward opening-up by synergizing the Belt and RoadInitiative and the Bangladesh-China-India-Myanmar Economic Corridor and?advancing the construction of?the Economic Cooperation Belt alongHimalayas. According to reports， with?an eye to Nepal， India and Bhutan， theEconomic Cooperation Belt aroundHimalayas will take Zhangmu， Gyirongand Pulan ports as the windows and Lhasa， Shaggiest?and other borderland?cities as the underpinning to?develop industries like border trade，?intonational?tourism， Tibetan medicine， agriculture and husbandry with Tibetan characteristics?and culture. Wang?Daiyuan， director of Tibetan Academy?of Social Science， believed that building the?economic cooperation belt will create?unprecedented opportunities for?Tibet's development. If these opportunities?can be seized， Tibet will?be able to achieve the upgrading in transportation， trade， finance， energy，?modern logistics and other sectors，?and thus advance its rapid economic?and social development.

Once opening to traffic， the Sichuan-Tibet Railway will certainly infuse strong impetus?into this development concept.In addition， the railway will also create a?passage between the Yangtze RiverEconomic Belt and the commodity passageway?to South Asia via the land route. By then， the railway will helpCentral China， East China and SouthChina find a way forward on a land route?to South Asia.

Wang also noted that in the long run， the Sichuan- Tibet Railway willplay an important role in integrating eastern?Tibet into Chengdu-Chongqing Economic Zone and adding?another dimension to Tibet-Sichuan traditional cooperation. AsChina's key traffic artery， railway is?the most important mode of modern transportation. Only by forming anetwork can the economic benefits brought?by railway transportation be maximized. In 2006， Qinghai- TibetRailway began operation， making railway?transport into Tibet possible for?the first time in history. Now， its strong boost?to economic growth has taken effect?in basic ways， and will become even?more prominent after it is linked with?the Sichuan-Tibet Railway to?form a ring line.

According to some estimates?，once completed， the Sichuan- TibetRailway will directly affect about520，000 square kilometers and about23.6 million people. In addition， it willdrive the construction of neighboring tourist?areas， like counties（districts）and cities of southwestern Sichuan and?northwestern Yunnan.?Within the?reach of Sichuan- . Tibet Railway，?cultural relics like Zhuokeji Chieftain' sFortress at Sichuan's Barkam Town?and over -4，000-year- old Karuo?Cultural Site at Tibet's Qamdo City?and ecological landscapes like snow mountains?and prairies， it abounds with?vast resources development and economic?growth potentials. However，?the underdeveloped transportation has remained?a long-standing barrier to its development， which will be removed by?the railway. "Transportation has been?a bottleneck for Tibet's economic?growth for a long time. Although the situation?is improving， it still remains a?some?what barrier to local development.Upon completion， the Sichuan- TibetRailway will provide a convenient and high- capacity option for Lhasa-boundtourists， thus converting external consumption?into internal consumption and?further booming Tibet's tourism，"Wang analyzed.

On hearing the news that the?Sichuan- Tibet Railway will breakground， Mr. Wang who opens aSichuan-style restaurant in Lhasa saidwith excitement， "It's reported that the travel?time from Lhasa to Chengduwill be reduced to over ten hours onceSichuan-Tibet Railway opens to traffic.Both my wife and I are overjoyed over?the news. Every year， we haveto experience a tough trip that lasts about?two days by train to go back toChengdu for the Spring Festival. Yet，?once the Sichuan-Tibet Railway begins operation， we can depart from Lhasain moring and arrive at Chengdu inaftemoon.'

As a super project that spans several?decades， the Sichuan-TibetRailway not only embodies the time and?energy devoted by enormous people?but also carries the expectation and?aspiration of myriad people. We?are hoping that by 2030， this "steel dragon" will fly above one after another mountain?and canyon into the far distance...