Chinese governments have ramped up investments in urban rail network constructions with local economic planning agencies fast tracking approvals of plans to boost growth in the world's second-largest economy.

Local bureaus of the National Development and Reform Commission in over 10 cities have granted approvals to build or extend local urban rail networks in recent months.

That, combined with previous plans by 2020, totaled some 4 trillion yuan in urban rail investment with the network extending to nearly 6,000 kilometers, the 21st Century Business Herald reported, citing Hua Maokun, former chief engineer of the defunct railway ministry.

Local NDRC agency in the megacity of Chongqing in central China announced over the weekend a plan to start construction of a new urban rail before the end of this year.

The project, with an estimated investment of 31.4 billion yuan, was the first organized by Chongqing following July's decentralization. Previously only the central government has the right to approve local rail network construction plans.

The city is also planning to extend an existing subway line, starting within the year and is expected to attract roughly 4.1 billion in investment.

A municipal tramcar line will be built in the southern city of Zhuhai with an estimated investment of 850 million yuan. In the western province of Gansu, some 18.9 billion yuan will be invested to build a subway line in its capital city of Lanzhou. Similar projects are being considered or approved in other cities including Hangzhou in Zhejiang Province, Huainan (Jinagsu), Wuhan (Hubei) and Changsha (Hunan), according to the newspaper.

China's State Council, the cabinet, said in late July that it planned to boost infrastructure construction in cities, with rail network one of the major areas.

The State Council meeting, chaired by Premier Li Keqiang, also vowed policy support to expand financing channels by attracting private investments.

Nearly all the cites, meeting the central government's requirements for railway network, are planning or building subway lines, said Wang Mengshu, a member of the Chinese Academy of Engineering. Wang was reportedly shuttling from one city to another, almost non-stop, offering advice to local governments.

A total of 36 local cities have approved plans to build subway lines, said Hua Maoun, estimating that by 2020 the country will have a rail network of nearly 6,000 kilometers in total.

That is in line with NDRC's expectation. An official with the NDRC told media the country will expand city rail network to 3,000 by 2015 and 6,000 by 2020, with combined investment at 3-4 trillion yuan.

In 2013 only, investment in rail network will expand 40 billion from last year to 220 billion yuan, according to calculations by the NDRC.