Shiziyang Tunnel

The Shiziyang Tunnel is a high-speed railway tunnel under Shiziyang, the northern part of the Pearl River estuary in China.

Route
The 10.8 km long tunnel is part of a 140 km-long high-speed line from Guangzhou to Shenzhen and Hong Kong. It is designed for speeds of up to 350 km/h (usually 250 km/h in operation) - 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 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 began on 26 December 2011. Unusually, the tunnel boring machines were designed to be dismantled inside the tunnel.