The underground pipeline network concept fluctuated and increased, and the Qinglong pipe industry was once close to rising and stopping, while subway design, Han Jianhe River and Mountain, Guanlong's energy saving, smooth control development, and Sanhe pipe piles followed suit.

The underground pipeline network concept fluctuated and increased, and the Qinglong pipe industry was once close to rising and stopping, while subway design, Han Jianhe River and Mountain, Guanlong's energy saving, smooth control development, and Sanhe pipe piles followed suit.