New progress has been made in the capacity expansion and renovation of the Nanjing–Wuhu Railway, which passes beneath Nonghua River, the Airport Expressway, and the Qinhuai New River. On June 18, with the capping of the roof slab of the shield launching shaft for the Nanjing South Tunnel, the conditions for launching the shield machine were basically met. Next, the "Ningwu" shield machine will successively enter the site for assembly, and the 2.4-kilometer underground crossing is counting down.

The Nanjing South Tunnel is a controlling project of the entire Nanjing–Wuhu Railway capacity expansion and renovation project, with a total length of 14.442 kilometers. It is a single-tube single-track tunnel designed for a speed of 120 km/h. The shield-driven section is about 2.4 kilometers long; the shield machine will be launched from the Meixiang Road working shaft in Yuhuatai District and will terminate at the existing Hanfu Mountain tunnel in Jiangning District for reception.

In view of the complex water conditions and surface and underground environments in the shield section, the project adopts the "Ningwu" shield machine jointly developed by the construction unit. The shield machine has an excavation diameter of 9.33 meters, a total length of 132 meters, and a weight of about 1,375 tons. It integrates multiple advanced intelligent technologies such as a visualized excavation chamber system and a shield tail brush wear detection system, and is equipped with wear-resistant inserted-tooth disc cutters and a single-pipe single-pump muck conditioning system, which will effectively improve the efficiency and quality of shield tunneling.

The shield section of the project successively passes beneath the Nonghua River and the Airport Expressway, crosses over Metro Line S1, runs parallel with Metro Line S3 over a long distance, and passes beneath the Qinhuai New River and the existing Beijing–Shanghai High-Speed Railway tunnel at Hanfu Mountain. Among these, the crossing beneath the Qinhuai New River is the most technically difficult, with the shallowest cover of only 2.6 meters, the shallowest cover ever encountered in a domestic shield project.

As the shallowest cover is less than one-third of the shield diameter, the contractor will use replacement backfill concrete at the riverbed to reinforce the cross-section, and add a reinforced concrete inner lining inside the tunnel to meet the anti-floating requirements of the tunnel underwater.

The main line of the Nanjing–Wuhu Railway capacity expansion and renovation project is about 102.2 kilometers long. It starts from Nanjing East Marshalling Station in the north, passes through Qixia District, Xuanwu District, Qinhuai District, Yuhuatai District, and Jiangning District of Nanjing, enters Ma'anshan City of Anhui Province, passes Dangtu County into Wuhu City, and ends at Wuhu East Station. Among these, electrification renovation is implemented for the section from Nanjing East Marshalling Station to Cangbomen and for the passenger train connecting line from Mennan Village to Nanjing Station; the existing railway from Cangbomen to Guxiong is relocated; and electrification renovation and the grade separation project are implemented for the section from Guxiong to Wuhu East.

The relocation of the line in the urban section of Nanjing (from Cangbomen to Guxiong) will effectively eliminate the safety risks of level crossings in the urban area and resolve the urban fragmentation, noise disturbance, pollution emissions, traffic congestion, and other current problems caused by the original line passing through the city. After the entire project is completed and put into operation, it will further optimize the regional railway network layout and is of great significance for accelerating the upgrading and adjustment of the industrial structure in areas along the line, optimizing the spatial layout of urbanization, and enhancing the flexibility of the road network.