青藏铁路.doc

1、Megastructures: Extreme RailwayNGC 全民英檢：偉大工程巡禮青藏鐵路This is the story of the battleto build a railway across one ofthe most extreme environments on earth.To lay over a thousand kilometres of trackin a remote wilderness.To drive seven tunnelsthrough the rugged slopesTo raise 675 bridgesover valleys and

2、 rivers.All at an altitude where even a simple breathis nearly impossible to come by.This is a tough place to work.Headaches, shortness of breath,freezing winds.140,000 workers and 2000 medicsstruggled for 5 yearsto conquer this hostile environmentand to complete.the Qinghai-Tibet railway-the highes

3、t, most extreme railwayin the world!Beijing West The largest station in Asia,and one of the busiest.400,000 can pass through here in a single day. Coming through with today s crowdis Finnish engineer, Pasi Lautala.He s here to see for himselfjust how one of the most extraordinary railwayson the plan

4、et was built-the line to Lhasa in Tibet.It goes so high and it goes forsuch a long distance over really rough terrains,so I don t think anything like thathas been ever donein the railway engineering world.This is no ordinary rail journey.The Lhasa express is a multi-billion dollarmarvel, specially b

5、uilt to survive at altitudeshigher than the Swiss Alps,and at freezing temperatures.For train-obsessed Pasi,its a journey hes dreamed about for years.I ve read about it, and I ve seensome of the engineering solutionsthey used to build the track.And I gotta see it.It s 9.30,and the Lhasa express is u

6、nder way.Well this is it. It s time to go.As Director of Rail Transportationat Michigan Tech University,Pasi is here on business.We re doing some workconnecting the Alaskan railroad networkwith the Canadian rail networkand as part of that projectwe ve been studying some ofthe cold region railroads a

7、round the world,to see how some of the other countriesand some of the other regions have built them.So it s a learning experience for me.From Beijing, the Lhasa expresswill travel 3000 km across Chinato the town of Golmud.From there the train will climbup to the Tibetan plateauand across the roof of

8、 the world to Lhasa.It s a marathon 47 hour journey,but its the final high-altitude sectionof the line that interests Pasi.It crosses land higher than any mountainin the American Rockies.An environment so hostilethat its like building a railway on Mars.And it took Chinese engineers 50 yearsto work o

9、ut how to do it.The idea to build this controversial railwaydates back to the 1950s.When the Chinese army occupied Tibet in 1950,they wanted a railway to supply the troops.But to build a railway,first they needed a roadThe Chinese governmentthrew a vast labour force,equipped with basic toolsagainst

10、the harsh conditionsof the Tibetan Plateau.But around three thousand workers died:from exposure and from altitude sickness.It was a disaster. And although the dream of a railway to Tibetlived on, the plans were eventually shelvedToday, the Lhasa Express pounds its wayacross industrial eastern Chinaa

11、t over 110 km per hour.It s the pride of Chinese railways,and only the best get to work on it.The thirteen passenger carriagesof the Lhasa express are dividedinto three types.Two so called “Soft Sleepers”are the Chinese equivalent of first class.Well this is definitely quite a luxurious wayof travel

12、lling, this compartmentis called the soft sleeper,theres 4 berths for 4 people,and we even have an entertainment systemwith some Chinese TV or movies,but it s not as luxuriousfor everybody in the train.Seven carriages offer“Hard sleeper” accomodation-a bit more of a squeezewith six people to a room.

13、And four carriages are simply fitted with seats.It may look like a normal trainBut later in the journey,the lives of everyone onboardwill depend on the hidden, high tech featuresof its carriagesThey ve been specifically builtto cope with the conditionson the Tibet plateau.When you take a look at the

14、se trains,they look just regular Chinese trains,there s nothing extraordinary,except I see this one here,it s an oxygen outlet,that you can get some extra oxygenin the high altitudes on the train.Each carriage is fitted withan oxygen generating unitthat will come into operationat high altitude. It s

15、 a small portentof what lies ahead.Throughout the day, the train heads West.Stopping for safety checks.And to pick up passengers.Lhasa is still 24 hours away,but already there are signsof Tibetan culture.As new passengers settle in for the night,the train is already climbing.By the time it reaches G

16、olmud,the last stop before the Tibetan plateau,it will be 2,800 metres above sea level.By three AM most of the passengersare fast asleep.But Pasi Lautala is wide awake.This is quite an exciting moment for me.In a few minutes were going to bereaching Golmud, which is the last stationbefore the train

17、climbs up the Tibet plateau.As I want to see how they built the track,this is the end of the line for me.It s time to get off.To find out how Chinese engineersconquered the plateau,Pasi needs to see the line-close up and in daylight.It s here, that the engineering challengereally begins.The remainin

18、g passengers are about toembark on a steep 2000 metre climb.And that means an engine change-to a loco with serious power.At very high altitudes a conventional dieselcan t cope with the low oxygen levels.So, bring on a pair of NJ2 locos.138 tonne diesel-electric monsters,with a combined output of 800

19、0 horsepower.Immediately behind the enginethey ve added an electricity generator car.This will be the train slife support system: supplying power, heatand most important of all,oxygen for the passengers and crew.The train is about to embarkon an extreme journey that is only possiblethanks to some ra

20、dical engineeringand a controversial political decision.By 1984, the Chinese railway systemhad reached Golmud But here it stopped.For the next 16 years, the unique problemsof constructing a railwayat very high altitudeblocked its progress to Lhasa.Then, in 1999 the Chinese governmentannounced that i

21、t wanted to extendits railway network to the poor,undeveloped regions of western China,and into Tibet.It argued that the railwaywould bring prosperity to the provinceand raise the standard of living.Chinas engineers had their workcut out to deliver on this bold planFifty kilometres outside Golmud,Pa

22、si Lautala begins his missionto find out how Chinese engineerssolved the first challengeof this extreme terrain.To reach the plateauthey had to first cross the formidable peaksof the Kunlun mountains.The old Tibetan highway runs closeto the new railway-giving Pasi the chance to drive the route.Well,

23、 when you see these Kunlun mountainswith their snowy tops,it s no longer surprisingit took 50 years to build this railway lineup here. Quite Magnificent.Cars and lorries can cope with steep climbs,but heavy trains need a slow gradual ascent-what engineers call a steady gradient.Well they ve chosen t

24、his routebecause this goes kind ofbetween the mountain tops.They are following the valley between,and that s the easiest wayto maintain the smooth gradient.But going straight up the valleyis out of the question-the gradient is too steep.So the railway must zig zag up it,crossing time and time again.

25、With literally dozens of bridgesTwo-thirds of the way up the valley,the engineers faced an enormous challenge-building the Sanchahe Bridge,the tallest bridge on the whole route.Right here we are crossing the river valleyso we have to maintain the railwayup in the air so that we can keepthe smooth gr

26、adient.Its a critical structurethat had to be completed quicklyso they could get suppliesup to the plateau by rail to build the restof the railway. And that meantworking through the winter.By throwing an army of workers at the job,and keeping the concrete warmwhen temperatures plunged to minus 20The

27、y managed to construct the bridgein just 12 months. The deadline was met.This is fantastic. Im quite happyI got off the train.And I can t even imaginehow it was to build this bridgeover the winter time. Just amazing.But this was just the beginning.As Pasi heads over the Kunlun mountainsup to the col

28、d, thin airof the Tibetan plateau, hes about to discoveran extraordinary natural phenomenonThat destroys towns!After crossing the Kunlun mountains,day breaks for the passengerson board the T27 train from Beijing to Lhasa.It brings with it spectacular viewsof the Tibetan plateau.I have dreamed to com

29、e to Tibetfor many years, and see the sceneryfrom the many books. And the sceneryis far more better than what we imaginedand from the book actually.Yeah, so it s really great.This incredible area is so vast and coldits been called the third pole.It stretches over 2 and a half millionsquare kilometre

30、s-a quarter of the area of China.Winter temperatures plunge tominus 35 degrees CelsiusAnd the entire areais higher than the MatterhornFor railway engineers, like Pasi Lautala,this is about as tough as it gets.If I was asked to build a railwayover these mountains, I would probablyrun away. I don t th

31、inkyou can find much more of a challengethan doing something like that.Actually you can!Because, below the flat surface of the plateau,lies a substance that for 50 yearsdefeated all attempts to build a railway-frozen earth“Permafrost”.Well the permafrost can have a depthof a few metres, or all the w

32、ayup to like 50 or 60 metres.And most of the permafroststays frozen year round.The problem is not the permanent permafrostdeep in the ground But a layerof soil and water above itthe “active layer”that freezes in winterAnd thaws in summer.In winter, the ground is frozen solid.But if I was here in the summer time,it would be like walking on a bogor a swamp.The effects of the winter freezecan easily be demonstratedIt s getting quite chilly here.so we re going to have a little experiment.