Agile Tibetan antelopes and stocky wild horses in a vast expanse of "home on the range" offered one of the most spectacular scenes to passengers on the first train to Tibet Saturday.

"Wow, what a lovely sight," the crowd exclaimed as they swarmed to the nearest windows to take a closer look at the critically-endangered species.

The train, coded "Qing 1" that left Golmud in Qinghai Province for Lhasa at 11:05 a.m., was driving through the Hoh Xil, China's largest area of uninhabited land but a natural habitat for 230 species of wild animals, Tibetan antelope in particular.

The population of Tibetan antelopes has dropped from several million to below 100,000 in the past two decades, a result of excessive poaching and human encroachment of their habitat.

International traffickers hunt the antelopes to make shahtoosh shawls, a luxury item that requires three to five pieces of antelope fur to make just one shawl.

Since 1979, the Tibetan antelope has been recognized as an endangered species and protected under the Convention on the International Trade in Endangered Species. Since 1989, the species has been listed as Class-A protected animal in China's Wildlife Protection Law.

China has established three nature reserves to protect the rare creatures, covering a total of more than 600,000 sq km, an area 40 times the size of Beijing.

One of them is located in Hoh Xil, a 45,000-sq.km area that has an average altitude of 5,000 meters and an average temperature of minus four degrees Celsius, with the lowest reaching minus 40 degrees.

How to build the Qinghai-Tibet Railway, the world's most elevated railway, through the Hoh Xil without encroaching on the animals' homes was one of the biggest challenges confronting the designers and builders of the railway.

For the first time in any railway project, the Chinese government spent heavily to build 33 green passageways for animals.

Construction work was suspended for several consecutive nights when female antelopes crossed the site while migrating to and from their breeding site in June and August of 2003, when the Hoh Xil section of the railway was being built.

To date, rare animals in the region have become used to the railway, said officials with the Hoh Xil nature reserve administration.

"They're no longer scared of the human work and cross the railway with ease," said Cega, director of the reserve administration in Qinghai Province.

A first group of 67 pregnant antelopes from the eastern part of the reserve crossed Wubei bridge of the Qinghai-Tibet railway on May 16 to give birth in the hinterland, according to Gelai, head of Wudaoliang station in the Hoh Xil reserve.

About 1,000 antelopes have crossed the railway via special passages so far, Gelai said. "Tibetan antelopes started migrating earlier this year than the past few years."

Throughout their maiden train ride across the "roof of the world", passengers are reminded of the environment issue and love for wild animals.

A guide for tourists along the "Heavenly Road", distributed to the passengers for free, says clearly the tourists should "cherish every single plant on the plateau" and must not disturb wild animals.

A miniature statue of a Tibetan antelope stands on every table in the train's dining car, reminding the diners to care for life.

Before the train left Golmud, Chinese President Hu Jintao emphasized the importance of environmental protection on the Qinghai-Tibet Plateau in a speech to mark the opening of the landmark railway.

"Railway workers and passengers traveling on the Qinghai-Tibet railway should consciously treasure waters and mountains as well as grass and woods on the Plateau, and they should help conserve the eco system and environment along the railway," Hu told an audience of 2,600 at the Golmud station.

After his speech, a train carrying officials and model workers on the project set out from Golmud for Lhasa where it was due to arrive on Saturday night. Another train set out from Lhasa.

Up to 1,000 Chinese journalists were dispatched to cover the events.

The central government spent 1.5 billion yuan (about 180 million US dollars) on environment conservation along the route, the largest amount in any single railway project in China.

"I do admire the Chinese government for that," said Italian sinologist Aldo Mignucci who is in Lhasa for a visit.

The 1,956-kilometer-long Qinghai-Tibet railway is the world's highest and longest plateau railroad and also the first railway connecting the Tibet Autonomous Region with other parts of China.

Environmentalists worry the railway and the influx of tourists into Tibet might threaten the local ecology.

Hoh Xil is also spelt as "Kekexili". Some say its name means " green hills" in Mongolian, while others say it means "pretty girls ".

The place has become famous since the showing around China of a film about the life-and-death fight between antelope poachers and vigilantes there.

The film, by Chinese director Lu Chuan, was based on the true story of a journalist who joined a Tibetan volunteer patrol chasing poachers trading in antelope wool. It was the first film shot on the Chinese mainland ever to win best feature film award at Taiwan's Golden Horse Awards - the Asian version of the Oscars.