A RAILWAY THROUGH THE ROOF OF THE WORLD

BEIJING — The inaugural journey for the world's highest railway began today, a technological feat improving China's access to one of the most forbidding corners of the Earth.

The quest to link China to the snow-covered plateaus of Tibet, known as the roof of the world, had been a dream of Chairman Mao's that dates back five decades. Technical difficulties in laying tracks over frozen mountain paths and on oxygen-starved peaks made it an impossible task at the time. But the Chinese government took up the challenge about five years ago and turned it into the centerpiece of a new drive to modernize western China.

For the Tibetan people who have been fending off Chinese cultural and political infringements since they lost their independence, the iron tracks mean something quite different. "The Chinese see it as a great technical achievement. We see it as a very sad moment in our history," said Tsering Jampa, a Tibetan who fled her homeland with her family after the 1959 uprising and now works as executive director of the Netherlands-based International Campaign for Tibet. "It's the final nail on the coffin to bring Tibet under Chinese control."

UPDATE: LHASA, Tibet — The first train from Beijing to Tibet finished its journey along the world's highest railway Monday, as pens spit ink and packaged foods burst in the low air pressure.

Laptop computers and digital music players failed because the tiny air bags that cushion their moving parts broke as the train climbed 16,640-foot Tanggula Pass.

Some passengers threw up. Others took Tibetan herbs or breathed oxygen through tubes. Outside, antelope and donkeys grazed beneath snowcapped mountains.

China says the stretch of track that links Lhasa to Golmud, which had been a final stop on China's vast network, is an unparalleled engineering feat.

The $4.2-billion project was built over four years on delicate permafrost, marshy ground easily damaged by human encroachment. Engineers used sunshades and high-tech cooling columns to help ensure that the ground stays frozen.

China has earmarked $190 million for environmental protection. But plastic bags, bottles and cardboard boxes were scattered along the railway, and large sections of earth were scarred by the tracks of vehicles. The government acknowledges that Tibetans have so far been largely excluded from the project but says more of them will be hired. Chinese state media says the railway will help double tourism revenue in Tibet by 2010 and cut transport costs for goods by 75%.