The Ministry of Railways is investigating a newspaper report that claimed fake materials were used in the construction of the Wuhan-Guangzhou high-speed passenger railway.

The Beijing-based China Economic Times reported yesterday that a large quantity of fake cold fly ash, a constituent of concrete, had been used along several hundred kilometers of the 93-billion yuan (US$12.24 billion) railway line, on which trains will travel at up to 350 kph.

The newspaper said construction contractors had been tricked into buying the fake material by unscrupulous suppliers and had used it widely, which might put the safety of the railway at risk.

An official with the Ministry of Railways, who asked not to be named, told China Daily yesterday that an initial investigation suggested the report had exaggerated some facts, such as the reference to the "wide" use of the fake materials.

The ministry will not, however, make an official statement until the investigation is completed, the source said.

The Wuhan-Guangzhou railway corporation also began its own investigation yesterday.

The presence of the fake material was discovered in March by an engineer surnamed Zhang.

While concrete was being pumped on site, a blockage occurred in the pipe, which is uncommon. After an investigation, Zhang suggested the concrete contained fake coal fly ash and that this might have led to the blockage.

Coal fly ash is produced from the burning of pulverized coal. It is a fine-grained, powdery material that is used in the manufacture of concrete.

Because the requirement for coal fly ash was "small", the railway corporation said it did not invite bids from suppliers as it had for other construction materials. Instead, it allowed the contractors to source their own suppliers.

However, in May, as demand for the coal fly ash began to soar to keep pace with the railway's construction schedule, fake products found their way on to the market.

To the naked eye, the fake ash looks identical to the genuine article, even to an experienced construction worker. Only laboratory testing can tell the two apart.

(China Daily July 5, 2007)