The Himalayan Express is the highest railway in the world and many experts said, quite simply, that it couldn't be built.
A train running 4000km from Beijing in China to Lhasa in Tibet, climbing up on to the Tibetan Plateau and reaching more than 5000m, over inhospitable and inaccessible permafrost landscapes, made massively difficult by winter conditions, was impossible. But, as I write this, lying back on my comfortable bunk, the Himalayan Express is quietly and smoothly scaling its serpentine track to the roof of the world. We have crossed the low grasslands in the afternoon and started the overnight climb to the Tibetan Plateau.
And, after a night rhythmic with the train, I wake to piercing blue sky, raw sun, sharp snow-capped peaks and yak herds. The land is a blond, sandy colour, with rivers frozen to mirror stainless steel.
We pass solitary homes with animal enclosures, yak herds and shepherds with sheep flocks and hawks.
A man in uniform salutes the train as it passes. Another man does the same. Then a boy.
On Cona Lake, the world's highest freshwater lake at 4800m above sea level, there are wild ducks as big as geese.
For the line, 550km of which is laid on permafrost, was completed with its 675 bridges of a combined length of 160km, and opened on July 1, 2006, a year ahead of schedule. The railway's average altitude through Tibet is 4600m, with temperatures dropping to -30C. The air oxygen content is just half of that at sea level.
Interestingly, less than two months later, on August 28, a 75-year-old Chinese man reportedly became the first passenger to die on the train, and there have been more since. It is said he had suffered heart problems beforehand, but insisted on travelling.
Indeed, everyone on the train up to Lhasa must fill out a Passenger Health Registration Card. It mainly warns against travel for those with severe heart, lung or respiratory diseases, but adds other conditions like "diabetes out of control, the hysteria" and "highly dangerous pregnant women".
In fact, no-one in our group seems to notice the altitude much, as we dine at 3400m and a steady 64km/h.
The dining car is comfortable and we are served eight dishes, costing 70 yuan (around $10) per person. There is soup and rice, a whole fish, shredded omelette and tomato, mushroom and bok choy, and potato, pork and beef dishes.
Yellow River beer for some, sweet hot coffee to follow for others.
The cabins are four-berth, with storage space for small cases and bags, and quite comfortable. I slept like a baby to the hushed rhythm of the train and its gentle rock.
The diesel locomotives were designed and built specifically for high altitude and can travel up to 120km/h where there is no permafrost, and 100km/h where the track is laid on permafrost. Signs throughout the train are in Tibetan, simplified Chinese and English. I don't spot any to advise against smoking, though officially it is a non-smoking train, and people do. There are no outdoor areas or opening windows, so the smell of cigarette smoke does rather pervade it.
The train reportedly has oxygen-enriched air, and there are personal air supplies, with individual masks, which travellers can plug in to.
To travel all the way from Beijing to Lhasa is 47 hours and just over 4000km, but Travel Directors chooses to fly to Xining and join the train there. Tony Evans, a director of the company and leading our group, feels that one day and night on the train is enough, and the spectacular scenery is all on this second day.
The train leaves Xining at 3.04pm and arrives in Lhasa, 1960km later, at 2.55pm the next day.
There are 45 stations along the line from Xinging to Lhasa, not that the Himalayan Express stops at many.
It passes the Chu'erma River Bridge, near the northern source of the Yangtze River, which is 2565m long and built for Tibetan antelope to migrate through, as the track crosses their natural path.
It passes the Tuotuo River, which is the source of China's longest river, the Yangtze, and it climbs to just over 5000m above sea level at Tanggula Pass. Tanggula is the highest station in the world.
It passes the 400sqkm of the Cona alpine lake, revered as holy by people in this area.
It passes Asia's biggest salt lake, Qarham Lake, and the Kunlun Mountains, which are an important pilgrimage site for Buddhists.
And the Geladaintong glaciers, snowy Dangla Mountain range, and northern Tibet's Young Tun Basin, a refuge for Tibetan antelope, wild yak and Tibetan wild donkey. It crosses the Qingshuihe Bridge - 11.7km long and 4600m above sea level.
And, travelling from Xining to Lhasa, it rises from the great expanses of grassland scenery and ranges that rise around the horizon slowly at first, golden in the afternoon sun of the first day, to the enormous and white-capped mountains that rise in the sharp morning light the next day.
To the roof of the world.
• The Himalayan Express is included on many of Travel Directors' trips from China to Tibet and Nepal. The 25-day Himalayan Express tour has departures on April 12 (escorted by Tony Evans), May 4, September 7 and October 5. After flying to China, the group connects with the train in Lanzhou for the journey to Lhasa in Tibet. The tour then travels by 4WD across the Himalayan Plateau via Gyangtse, Shigatse, Tingri, Everest Base Camp (conditions permitting) and on to the border town of Zhangmu. Then it's on to Kodari and Kathmandu before flights to Bhutan. The tour costs $14,597 per person, twin-share.
The 20-day Himalayan Adventure begins in Beijing and travels by train to Lhasa following the same route to Kathmandu by bus before flights back to Australia. The tour costs from $7997 and has departures on April 20 and October 5. The 18-day Riding The Roof motorcycle tour follows the same route from Lhasa to Zhangmu, then the group rides into Nepal to Dhulikhel, Pokhara and Kathmandu, before flying home. There are departures on May 12 and October 6 on the tour which costs $10,997 per rider and $10,497 for a pillion passenger.
All tours include international and domestic flights, taxes, visas and courier fees, all accommodation, meals, ground transportation and transfers,entrance fees and tips and gratuities. For Travel Directors phone 9242 4200, call at 137 Cambridge Street, West Leederville, or see traveldirectors.com.au.
• Stephen Scourfield and Tony Evans will speak about the Himalaya tours on December 1 at 2pm at Travel Directors. Bookings are essential. Call 9242 4200.
• Singapore Airlines flies from Perth four times daily (from October 28 to March 30), with direct connection from Singapore to Beijing. I left at 4pm and arrived at 7am the next morning, local time. Travel agents and singaporeair.com.
Stephen Scourfield travelled as a guest of Travel Directors and Singapore Airlines.