Nanning Rail Transit Line 4 Phase I Is Now in Full Operation

On September 26, the Nanning Rail Transit (NNRT) Line 4 Phase I, designed by Beijing Urban Construction Design & Development Group, achieved full-line operation. This east-west backbone route, running along the southern bank of the Yongjiang River, plays a key role in advancing Nanning’s urban strategy of “improving the northern region, enhancing the southern region, and focusing on southern development”. It is significant for shaping the city’s layout, improving the rail transit network, and supporting the development of the Wuxiang New District.

NNRT Line 4 Phase I begins at Hongyun Lu Station and ends at Longgang Station, covering a total length of 25.05 kilometers. The line includes three transfer stations, i.e., Advanced Business Park Station, Dashatian Station, and Nahong Overpass Station, connecting with Lines 3, 2, and 5. It serves as a key route crossing the Wuxiang New District, linking the Yongning Longgang area with the central urban area. With the official opening of Qingpingpo Station and Longgang Station, NNRT Line 4 Phase I is now fully operational.

During the project implementation, UCD’s project team, leveraging exceptional technological innovation, successfully created this underground urban artery. In terms of energy-saving and environmental protection technologies, the team pioneered a new air conditioning system solution and achieved significant breakthroughs. This solution integrates water-cooled direct expansion (DX) units, water-cooled multi-split systems using double-pipe heat exchangers, hydraulic circulation clean modules, and independent water-cooled DX energy-saving control systems. At Nahong Overpass Station in the first opened section, tests demonstrated remarkable results, and stations that opened later further optimized the design. The project has become a model for energy conservation, emission reduction, prefabricated equipment rooms, and smart operation in rail transit.

The geological conditions of the platform-level tunnel at Wuxiang Railway Station in the later opened section are complex, with the need to simultaneously tackle high-strength karst limestone and water-sensitive argillaceous siltstone, thus posing significant construction risks. The design team utilized dynamic design, implemented flexible excavation and groundwater control solutions, and successfully addressed multiple on-site hazards such as water seepage and softening, ultimately ensuring the safe completion of the tunnel.

A decade of effort culminates in the realization of a dream. Since 2015, UCD’s project design team has overcome a series of challenges in schedule, design, geology and coordination, and ultimately achieved the goal of high-quality operation. Moving forward, UCD will continue to uphold its craftsmanship spirit and contribute to the sustained elevation of Nanning’s urban development level.