JINAN - The Watang-Rizhao Railway, China's longest heavy haul line, connecting the inland coal-producing province of Shanxi with a port city in the neighbouring Shandong province, went into operation on Tuesday.

The 1,216 km line with an annual capacity of 200 million tons connects Watang township of Xingxian county, Shanxi province with the coastal Rizhao city in Shandong province.

At a cost of 106 billion yuan ($17 billion), the railway was paid for by the China Railway Corporation, the provincial governments of Shanxi, Henan and Shandong, Bank of China Group, China Datang Coal Industry Co Ltd and China Huadian Corporation.

The opening of the railway is important for energy security and the economic development of the provinces along the line, according to an official with the Shandong provincial development and reform commission.

Currently the 653 km Datong-Qinhuangdao railway is the artery of China's coal transportation.

As a leading mining region, Shanxi has produced a total of 14.5 billion tons of raw coal since the founding of the People's Republic of China in 1949.