Its name is derived from its two terminal cities, Datong, a coal mining center in Shanxi province, and Qinhuangdao in Hebei province, on the Bohai Sea.

The electrified double track line serves as a major conduit for moving coal produced in Shanxi, Shaanxi, and Inner Mongolia to Qinhuangdao, China's largest coal-exporting seaport, from there coal is shipped to south China and other countries in Asia.

[2] Design capacity was 100 million tonnes a year, which it reached after ten years, but continuous upgrades (wider subgrade, 75 kg/m rails, wagons with higher capacity and top speed, longer trains and stronger locomotives, radio operation and centralised traffic control, automatic train inspection) quadrupled capacity.

[3] In 2006, powerful locomotive models HXD1 and HXD2, with 9.6 MW and 10 MW power output respectively, entered Daqin line to replace the older DJ1 models.

[14] 14 April 2022 - 17 cars of a freight train derailed after colliding with a parked locomotive near Cuipingshan railway station in Jizhou District, Tianjin, 11 of which fell off from the elevated railway.