The Shanghai Daily reported yesterday that the tracks under the world's first commercial magnetic-levitation train are sinking, which could possibly pose a threat to the US$1.2 billion project, the Shanghai Daily reported yesterday.

The 430kmh maglev began operating this year, linking Shanghai's new international airport with its eastern financial district. "We have been aware of the sinking of our maglev track," a spokesman for the train company was quoted as saying.

German companies spent decades and billions of dollars developing the maglev technology, but searched in vain for buyers until Shanghai leaders picked it to highlight the city's high-tech ambitions. Sinking tracks are not the only problem facing the maglev, which uses a powerful magnetic field to suspend trains millimeters above their rails and propel them at jet plane speed. The 440-seat trains reportedly carried an average of just 73 passengers a day last month.