The total length of China's railways has expanded to 3,612 kilometers by the end of 2015, and another 3,000 kilometers of mass transit railways are under construction, according to China's top economic planner.

Hu Zucai, vice chairman of the National Development and Reform Commission, told a Friday news conference that besides the 26 Chinese cities that have built metro systems, another 39 cities have got their metro system planning approved, with a total of 3,000 kilometers of rail lines under construction.

Earlier data from the China Association of Metros showed that 15 new urban rail lines of 438 km have become operational in 2015, adding to the total of 3,612 km of railway networks.

Of these operating lines, 2,658 km are subways and 239 km are light rails, the association said.