Like exhausted but triumphant climbers, pudgy Chinese officials wheezed between smiles atop Kunlun mountain pass, before their oxygen-outfitted locomotive whisked them southwards along bare-backed snowy peaks to the Tibetan border.
It was not surprising that the handful of visiting party elite were gasping for air - at 4,780 metres (15,682 feet) Kunlun in China's western Qinghai province is one of the highest passes along the new Tibet railway that is rapidly nearing completion.
When this mammoth feat of high-tech engineering embarks on its maiden trial run next July to the heart of Tibet's capital Lhasa, it will have huffed through 1,142-kilometres (708-miles) of some of the earth's most rugged and inhospitable terrain.
Once signalling and track testing finishes in the next 16 months, it will be possible to travel from Beijing to Lhasa in 48 hours, connecting China to the remote Buddhist territory by rail for the first time.
Passengers will sit back in the luxury of Canadian-built pressurised cars as they traverse the brown, oxygen-thin moonscape of the Tibetan plateau at a maximum altitude of 5,070 meters (16,633 feet) above sea level.
The train is also expected to tighten Beijing's political control over a rebellious Tibet, a country annexed by China in 1951, whose culture is threatened by the flood of immigrant Han Chinese, only expected to multiply with the official opening of the rail sometime in 2007.
At such dizzying elevations the Chinese engineered project has encountered a string of knotty technical problems, including laying track on frozen ground that melts in summer and ecological conservation issues.
Nevertheless, with only some 70 kilometres (44 miles) of construction to go in the 30-billion yuan (3.7-billion dollar) project, a cost 10 times the annual education budget of Tibet and Qinghai combined, officials are claiming success.
"I think it will play a great role ... and it will help people get rich in the region," said Su Sen, vice governor of Qinghai.
For the labourers laying track at average altitudes of 4,000 metres (13,123 feet), it has been breath-depleting work, forcing the government to establish along the route oxygen-providing clinics to combat altitude sickness.
Even so, the gruelling conditions have claimed lives, say local residents in Golmud, where the project began in 2001.
Li Long, who has ferried a top city official to the construction site for the last four years, said deaths had occurred.
"Definitely! There have been deaths from altitude sickness. Not many, a handful," said Li.
Officials in Golmud, a poor and small city that for the past two-decades has served as a transit point for travellers on the road to Tibet, admit only to an unspecified number of traffic-related deaths.
"Trucks have flipped over but nobody has died from altitude sickness," insisted city mayor Du Jie.
Despite the risks, some 50,000 labourers from China's poorest regions have flocked to the project for the chance to earn in 20-day shifts some 2,000 to 3,000 yuan (246 to 370 dollars) a month.
"It's an extremely tough job, but people do it for the high salaries," said Zhang Quanguo, who for three years trucked in parts to the railway until sudden arthritis in his left knee made it too painful to shift the clutch.
Now, perched on a stool outside Lucky's, his makeshift roadside shop, Zhang watches the single white locomotive cruise by several times a week carrying chuffed communist party elite on back-slapping inspection tours.
With most of the construction having crossed the border into Tibet last year there are few workers to buy his cheap tobacco and drinks. "I will probably head home to Gansu (province) next year," he said.
That is not the case for Zhang Zhonglian. As the chief engineer waited stiffly for his privileged passengers to return to the comfort of leather sofas, oxygen tanks, fruit bowls and a television, complete with a wall-covering picture of Chinese President Hu Jintao, Zhang admitted to his high hopes.
"I can't say for sure, but I'm a pilot and hope that I will be driving the new train next year," said Zhang, from China's northern Shanxi province.
"For now the train is used according to the needs of our leaders."