Construction Completion of Shanghai Metro Line 4 Outer Loop

On December 20, 2004, Shanghai Metro announced the completion of primary civil construction on Line 4’s outer loop, a significant milestone in the rapid expansion of one of the world’s fastest-growing urban rail networks. Line 4 was designed as a near-circular orbital route to relieve pressure on central interchange stations and improve connectivity between districts along the Huangpu River. Completing the tunnels and main structures allowed for track-laying, electrical installation, and testing to accelerate. Portions of the loop opened in late 2005, with full completion in 2007 after additional safety work on river-crossing tunnels. The project helped Shanghai transition into a modern megacity with robust rail mass transit, influencing Chinese metro construction standards nationwide.