WUHAN - China's first subway line to cross the Yangtze River, the country's longest waterway, is expected to start test run this month in the central city of Wuhan, local officials said Tuesday.

Subway trains have run through the 27.73-km tunnel for Wuhan Line 2, which links Wuchang and Hankou -- two major areas of the city -- over the past three months. But passengers will only be allowed to board the trains on Dec 28 when the test run starts, officials with the Hubei provincial transportation bureau said.

The subway line has recently passed the experts' assessment, they said.

It will be Wuhan's first subway, which is estimated to transport at least 600,000 passengers daily by 2015.

As a key transportation route, the line is expected to handle half of the city's cross-Yangtze traffic flow, easing gridlock on bridges over the river.

The construction costs around 14.9 billion yuan ($2.37 billion), according to estimates by previous reports.

The 6,300-km Yangtze River, which originates in northwest China's Qinghai province and flows through 10 provinces and municipalities before emptying into the East China Sea, is a major transport link between the west and east China. More than 100 bridges across the river are in use.

Wuhan lies at the intersection of the Han and Yangtze rivers. Its city proper is divided into three major areas by the rivers.