Electricians set the electric system for a railway line linking Xinfeng and Yaocun in Xi'an, capital of northwest China's Shaanxi Province, Jan. 7, 2020. The 23.1-kilometer railway line will help ease the traffic pressure of Xinfeng Railway Station in Xi'an. (Xinhua/Liu Xiao)

Aerial photo taken on Jan. 7, 2020 shows builders working at the construction site for a railway line linking Xinfeng and Yaocun in Xi'an, capital of northwest China's Shaanxi Province. The 23.1-kilometer railway line will help ease the traffic pressure of Xinfeng Railway Station in Xi'an. (Xinhua/Liu Xiao)

An electrician sets the electric system for a railway line linking Xinfeng and Yaocun in Xi'an, capital of northwest China's Shaanxi Province, Jan. 7, 2020. The 23.1-kilometer railway line will help ease the traffic pressure of Xinfeng Railway Station in Xi'an. (Xinhua/Liu Xiao)

Builders work at the construction site for a railway line linking Xinfeng and Yaocun in Xi'an, capital of northwest China's Shaanxi Province, Jan. 7, 2020. The 23.1-kilometer railway line will help ease the traffic pressure of Xinfeng Railway Station in Xi'an. (Photo by Han Zhengyang/Xinhua)

Electricians set the electric system for a railway line linking Xinfeng and Yaocun in Xi'an, capital of northwest China's Shaanxi Province, Jan. 7, 2020. The 23.1-kilometer railway line will help ease the traffic pressure of Xinfeng Railway Station in Xi'an. (Xinhua/Liu Xiao)

Builders work at the construction site for a railway line linking Xinfeng and Yaocun in Xi'an, capital of northwest China's Shaanxi Province, Jan. 7, 2020. The 23.1-kilometer railway line will help ease the traffic pressure of Xinfeng Railway Station in Xi'an. (Photo by Han Zhengyang/Xinhua)

An electrician sets the electric system for a railway line linking Xinfeng and Yaocun in Xi'an, capital of northwest China's Shaanxi Province, Jan. 7, 2020. The 23.1-kilometer railway line will help ease the traffic pressure of Xinfeng Railway Station in Xi'an. (Xinhua/Liu Xiao)