A Tibetan antelope runs briskly after a four-wheel drive vehicle towards the three sheds that serve as a wildlife preservation center in the Hoh Xil Natural Reserve 4,600 meters above sea level.

It apparently recognizes the car and its driver Gama - many Tibetans have no surnames - a worker at the center.

Gama became the animal's means of survival in June 2006, when it was found alone in the wild, barely a week old and with an injured leg. He took it to the center, tended its wounds and kept it at the nature reserve alongside other Tibetan antelopes, stocky wild horses and donkeys.

He named it Nima, which means "the sun" in Tibetan.

Gama and his colleagues work to protect wild species in Hoh Xil, a 45,000-square-kilometer area in Tibet that is an ideal habitat for wild animals.

"Nima was obviously scared when the first train leaving Lhasa passed Hoh Xil," says Gama. "She was barely a month old and had never seen or heard a train. So she ran."

Today, a daily average of six trains pass their home, but Nima and the other animals are no longer afraid. "They simply stop grazing and look."

Doubts and criticisms are part of the history of the "heavenly railway" even when it was still on the drawing board. The possible extinction of the critically-endangered Tibetan antelopes has been frequently cited by some environmentalists in arguments against the railway.

At the wildlife preservation center, visitors have poured in. "Many chipped in preservation funds. Some offered to work as volunteers," says Gama.

Tibet used to have several million Tibetan antelopes, but excessive poaching and human encroachment on their habitats caused the population to shrink sharply in the past decades.

Until the mid 1990s, up to 4,000 antelopes in Tibet were killed by poachers each year. Tibet has tightened supervision and patrols in the antelopes' habitats since 1998, and established three nature reserves to protect the creatures, covering more than 600,000 square kilometers.

The government made wildlife preservation a priority in its construction of the railway to Tibet. Thirty-three special passageways were built along the line, enabling animals to follow their normal migratory routes unhindered.

Last year, a Chinese forestry administration report put the population of Tibetan antelopes in Tibet at 150,000, doubling the number of the late 1980s. Hoh Xil alone has 50,000 antelopes.

"Next year, when we mark the second year of the railway, we'll set Nima free far from our preservation center. It'll be the time for her to return to the wild," says Gama.

"Very likely train passengers next year will see flocks of pregnant antelopes migrating to their breeding sites. Nima could be one of them," Gama adds.

Editor: Cindy