Freight trains from Hebei province's Shacheng to Beijing's Fengtai have been equipped with special anti-smog technology to ensure the security of trains, the Beijing Youth Daily reported.

The technology invented by China CNR Corporation has already been used on HXD2 locomotives, built in collaboration with French firm Alstom.

The technology is to be applied to other electric locomotives this year. Experts have said that metal particles pose safety risks to electric locomotives.

The country's first anti-smog HXD3D locomotives by Dalian Locomotive and Rolling Stock Company, which can reach a speed of 160 kilometers per hour in smog, were put into operation early this year.