China has succeeded in solving a series of technical problems in building the Qinghai-Tibet railway, the highest railway in the world.

Chinese railway builders and scientists have developed effective ways, based on experimentation and experience in constructing the railway in the past year, to treat major problems like highland cold, water and oxygen shortages, and frozen earth.

The 1,118-km (695 miles) railway will extend from Lhasa, capital of the Tibet Autonomous Region in southwest China, to Golmud in Qinghai Province in the northwest.

More than 960 kilometers (597 miles), or over four-fifths, of the railway will be built at an altitude of more than 4,000 meters (13,123 feet) and 547 kilometers (340 miles), or more than half of its total length, will be laid onlong-frozen earth.

To guarantee the stability of the railroad bed and the safe operation of the railway, scientists and builders have tried to avoid laying rails in areas with severely frozen earth, and built bridges over some areas where the frozen earth is unstable, or ventilation dykes and paved layers to preserve the frozen earth.

A research report by the Xibei (northwest) Science Research Institute under the China Railway Engineering Corporation shows that thermosiphons are expected to help resolve problems resulted from the frozen earth.

The report said experiments showed the use of thermosiphons to cool the railway bed was feasible.

Experts explained that thermosiphons transmit heat in one direction, which means heat will be transmitted from underground to the surface, but cannot be transmitted from the surface to below ground.

Wide use of thermosiphons could help preserve the frozen earth,they said.

Chinese scientists started research on the frozen earth as early as since the early 1960s.

Experiments involving new technologies, techniques and materials are going well in five frozen earth areas along the railroad.

Meanwhile, breakthroughs have been made in solving shortages of oxygen and water.

No deaths caused by pulmonary edema and cerebral edema, the aftermath of oxygen shortage at altitude, have been reported on the construction site since the railway project was launched one year ago.

China has been considering building the Qinghai-Tibet railway for more than five decades. Rapid economic growth and technological advances over the past two decades have made the project possible.

Upon completion in six years, the railway will end a history of the Tibet Autonomous Region being inaccessible by train.

(People's Daily July 13, 2002)