China's rail freight volume, an indicator of broad economic activity, rose 9.1 percent year on year in 2018, according to the China Railway Corporation.

Railways carried 4.02 billion metric tons of freight last year, 334 million metric tons more than the previous year, data from the company showed.

Of the total, state-operated railways carried 3.19 billion metric tons of cargo, up 9.3 percent or 272 million metric tons. Compared with highway freight, the increased rail freight could save 2.99 million metric tons of standard coal and reduce emissions of carbon dioxide by 7.36 million metric tons.

Apart from state-operated railways, China also has rail lines operated by local governments and enterprises.