China’s capital Beijing is trialling its $2.2bn Metro Line 4, the city’s first public-private railway partnership with Hong Kong.

The 29km underground line runs from Gongyixiqiao, on the South Fourth Ring Road, to Anheqiaobei, in the north-western Haidian district, via Xizhimen.

The rail line covers 24 stations and is expected to cater to nearly 700,000 people daily.

The line was built by Beijing MTR Corporation, a joint venture company comprising MTR Corporation, Beijing Infrastructure Investment and Beijing Capital Group.

The build-operate-finance contract was awarded by Beijing Municipal Government in 2006.