China's new train from Beijing to Tibet arrived in the ancient capital of Lhasa Monday, ending its maiden journey after climbing to elevations so high that ballpoint pens and packaged foods burst.

Some passengers breathed oxygen from tubes - many just out of curiosity - as the pressurized train crossed a 16,640-foot pass in Tibet's Tanggula Mountains, a height the Chinese government says makes the US$4.2 billion railway the world's highest.

A train crew demonstrates the use of oxygen tubes on board the first Beijing-to-Lhasa train during a stop in Golmud, northwestern Qinghai province July 3, 2006. The 4,000-km (2,500-mile) journey will reach altitudes of over 5,000 metres (16,400 feet) on the Tibetan plateau. [Reuters]

Girls in track suits and traditional Tibetan robes draped white scarves, a customary greeting, on passengers arriving in Lhasa's new railway station.

The US$4.2 billion train is a new tool in China's push to bind its booming east to the Himalayan "roof of the world."

It is hoped the line would bring greater prosperity to the region.

Trains completed shorter trips on the line between Lhasa and Golmud in Qinghai province while passengers on the 16-car train from the Chinese capital were in the midst of their journey.

Before the last leg of the trip to Lhasa, the train stopped in Golmud early Monday to switch its standard engine for three powerful locomotives required to haul the train at high altitude.

The only signs of human habitation in the arid highlands south of Golmud were occasional small train stations and herders tending yaks.

After the train climbed above 13,000 feet, pens and bags of processed food burst due to the low air pressure. Laptop computers and digital music players failed, because moving parts in their disk drives are cushioned by tiny air bags that break at high altitude.

The railway is projected to help double tourism revenues in Tibet by 2010 and cut transport costs for goods by 75 percent. Until now, goods going to and from Tibet have been trucked over mountain highways that are often blocked by landslides or snow, making trade prohibitively expensive.

Work on the rail line began in 2001, after engineers worked out how to stabilize tracks on permafrost.