Workers are driving trucks and shuttling back and forth on designated makeshift roads. Preheated water and sand are used in concrete mixers clouded in white steam.

Several hoardings displaying green grass and blue skies stand out in the dull winter. The hoardings remind workers to be environmentally friendly, saying "Taking good care of the plateau prairie", "Cherishing the plateau eco-system by building a 'green' railway", and "Wild plateau animals are our friends".

Unlike in summer, each worker is now carrying an oxygen bag on the back. Extra oxygen cylinders are also kept in the entrance ways.

"People are more likely to suffer from anoxia in winter as grass withers and tree leaves fall," said Zhang Xiuli, engineer for the headquarters of the Qinghai-Tibet Railway construction.

The altitude of the section now being constructed is between 4,000 to 5,000 meters. Doctors keep moving around the site to see if anyone needs help.

"To date no one has had a health problem caused by anoxia," Zhang said.

He said that most construction work has been suspended due to the winter weather. However tunnel digging and bridge building, which decide the pace for track laying, will be continued throughout the winter.

Other projects continued throughout winter are those the commencement of which is an essential to the overall construction timetable, he added.

More than 8,000 workers are expected to participate in winter construction work. Work in the wild is restricted to no more than six hours a day or in a tunnel no more than four hours, according to new rules issued by the headquarters.

Nutritionists work out menus to guarantee that every person receives enough nutrition and calories. Fresh meat, vegetables and fruits are transported everyday from Golmud to the construction sites which are scattered over 100 km of the Qinghai-Tibet road, which lies parallel to the railway under construction.

As many machines as possible are used to reduce the intensity of the work. "The intensity of the work is below the medium expected," says the engineer.

Construction work is well under way, he explained from the latest construction schedule.

Zhang said that headquarters have adopted construction and health care plans which adapt to the special climate on the Plateau, to ensure workers' health and the quality of construction work.

The mixture in the concrete mixer must be heated and its temperature should be 10 to 20 degrees centigrade. Containers are wrapped with cotton blankets to keep the mixer warm. Tubes piping concrete to the construction site are made of thermal insulation materials. Steam is blown onto newly poured concrete bases to avoid glaciation before solidification.

"Such measures are efficient and make bridge bases as firm as those built in other warmer seasons," Zhang said, "by doing this we are able to meet the strict standards set for quality examinations."

Construction of the 1,118-km Qinghai-Tibet Railway began on June 29 this year. More than 960 km, or over 80 percent of the railway will be built at an altitude of more than 4,000 meters. It will be the longest and most elevated railway to be built on any highland in the world.

(People's Daily December 31, 2001)