The Shiziyang Tunnel is a high-speed railway tunnel under the Pearl River

Pearl River (China)

The Pearl River or less commonly, the "Guangdong River" or "Canton River" etc., , is an extensive river system in southern China. The name Pearl River is usually used as a catchment term to refer to the watersheds of the Xi Jiang , the Bei Jiang , and the Dong Jiang...

 estuary in China

China

Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...

.

Route

The tunnel is part of a 140km high-speed line from Guangzhou

Guangzhou

Guangzhou , known historically as Canton or Kwangchow, is the capital and largest city of the Guangdong province in the People's Republic of China. Located in southern China on the Pearl River, about north-northwest of Hong Kong, Guangzhou is a key national transportation hub and trading port...

 to Shenzhen

Shenzhen

Shenzhen is a major city in the south of Southern China's Guangdong Province, situated immediately north of Hong Kong. The area became China's first—and one of the most successful—Special Economic Zones...

 and Hong Kong

Hong Kong

Hong Kong is one of two Special Administrative Regions of the People's Republic of China , the other being Macau. A city-state situated on China's south coast and enclosed by the Pearl River Delta and South China Sea, it is renowned for its expansive skyline and deep natural harbour...

. It is designed for speeds of up to 350 km/h - the fastest underwater tunnel in the world. as well as being China's longest underwater tunnel. This allows rail journeys between Guangzhou and Hong Kong to take only 40 minutes - much faster than the previous 2 hour journey. The Guangzhou-Shenzhen-Hong Kong express rail link

Guangzhou-Shenzhen-Hong Kong Express Rail Link

The Guangzhou-Shenzhen-Hong Kong Express Rail Link Hong Kong Section is a proposed high speed railway connecting Kowloon with the high-speed rail network of China at Shenzhen...

 is part of a broader expansion of high speed rail in China; journeys from Beijing to Hong Kong will take only 8 hours.

Construction

Construction began in November 2007, with a budget of CNY2.4 billion; the tunnel was completed in 2011, and passenger services are expected to begin in 2012. Unusually, the tunnel boring machines

Tunnel boring machine

A tunnel boring machine also known as a "mole", is a machine used to excavate tunnels with a circular cross section through a variety of soil and rock strata. They can bore through anything from hard rock to sand. Tunnel diameters can range from a metre to almost 16 metres to date...

were designed to be dismantled inside the tunnel.