CHANGSHA -- China's self-developed tunnel boring machine with the biggest diameter has been rolled off the production line on Thursday.

The machine, with a maximum excavation diameter of 16.64 meters, was produced in Changsha, capital city of Central China's Hunan province.

Developed jointly by the China Railway Construction Heavy Industry Co., Ltd. (CRCHI) and China Railway 14th Bureau Group Co., Ltd., it is 145 meters long and about 5,000 tonnes in weight. Its circular cutter's diameter is equivalent to a five or six-story building.

According to Zhao Hui, chairman of the CRCHI, production of the tunnel boring machine marked a breakthrough in the development and industrialization of the 16-meter-class domestic super-large diameter tunnel boring machines.

The new machine is expected to be used in the construction of a large-scale tunneling project under the Yangtze River, which is intended to establish a major trans-river road link under the country's longest river, connecting Nantong city with Taicang city in East China's Jiangsu province.