China's first train from Beijing to Tibet crossed into the poor and arid highlands of western China on Sunday, turning heads as it made its slow climb from the nation's capital to the forbiddingly high Tanggula Pass in the Himalayan region.

Cornfields, factories and coal mines gave way to melon patches, herds of sheep and honey farmers as the train moved further west at a speed of about 75 mph into Qinghai province where incomes hover around $300 a year.

By late Sunday, 24 hours after it left Beijing, the train was halfway to its destination — the Tibetan capital of Lhasa.

The $4.2 billion railway, an engineering marvel that crosses mountain passes up to 16,500 feet high, is part of the government's efforts to develop China's poor, restive west and bind them more closely to the country's booming east.

Many Tibetan passengers spoke glowingly of the railway, but it was unclear whether these were candid answers as dozens of foreign ministry officials were also onboard.

A 23-year-old Tibetan who gave his name as Suoping was returning home to look for a job after graduating from the Beijing Police Academy. He said the train would bring economic benefits to the Tibetan region.

"Our biggest problem has been the transportation issue. With the opening of the rail, there should be lots of new business opportunities," he said.

Suoping said the establishment of the rail line in the region could result in increased pollution, but added he was confident the government would address such problems.

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.

Yet, as with so much else in China's often harsh 56-year rule over Tibet, the railway has drawn controversy.

Activists warn it will bring a flood of Chinese migrants, diluting Tibet's unique Buddhist culture and threatening its fragile environment. They say most of its economic benefits will go to migrants from the east.

New York-based Students for a Free Tibet set up a Web site, rejecttherailway.com, urging the public to wear black armbands in protest of the project, which the group says "is a tool Beijing will use to overwhelm [the] Tibetan population."

"We reject the railway just as we reject China's illegitimate rule in Tibet," the group wrote in a message on the site.

Communist troops marched into Tibet in 1950, and Beijing says the region has been Chinese territory for centuries. But Tibet was effectively independent for much of that time.

The rail line is the realization of a decades-old dream by Chinese officials and engineers. Abandoned plans were resurrected in 2001 after engineers came up with solutions for stabilizing tracks on permafrost.

On the train, passengers passed the time by playing cards, singing traditional Tibetan folk songs and discussing the latest World Cup results, which they received via text message on their mobile phones.

Special features in the cabin include oxygen-enriched air to help passengers cope with the altitude, garbage containers with built-in compacting pressers and anti-lightning equipment on the roof.

Before the last leg of the journey from the far western frontier town of Golmud to Tibet's capital of Lhasa, rail staff will switch from the ordinary single locomotive to three specially imported GE-manufactured locomotives to aid the final climb up to the 16,640-feet high Tanggula Pass.

The 710-mile final stretch of the line linking Golmud with Lhasa crosses some of the world's most forbidding terrain on the treeless Tibetan plateau. The railway's highest station is in Nagqu, a town at 14,850 feet in the plateau's rolling grasslands. China says this stretch of rail line is the world's highest.