Second Phase of Chongqing Metro Line 4 Opened to Traffic

On June 18, the second phase of Chongqing Metro Line 4, which UCD undertook the survey and design general contracting tasks, was put into operation. The opening of this project will substantially improve the travel efficiency and quality of residents along the line, facilitate the coordinated development of peripheral groups and the central city, and boost the high-quality development of rail transit in Chongqing.

The second phase of Line 4 is one of the backbone lines of the rail transit lines in Chongqing, with a total length of 32.8 kilometers. Many new concepts and technologies have been adopted for the project design, such as the organic integration of 20,000 square meters of underground space with the track to enable the track to better serve urban development. The first-ever adoption of the "coupled" smoke exhaust technology in China has turned out an effective solution to disaster prevention in long and spacious tunnels. The entire line of assembled ballast beds (including depots) has been implemented, and prefabricated stairs, shafts, partition walls, and inspection pit columns and other assembly technologies have been used on a pilot basis for the very first time in China. The design team has also actively practiced smart construction, with BIM design used all through to build a full-line intelligent operation and maintenance platform based on BIM, and piloted the use of smart station technology and the integrated design of station weak current housing, which has improved the intelligence level of the project.

It is reported that after the opening of the second phase of Metro Line 4 the operating mileage of rail transit lines in Chongqing has reached 450 kilometers.