WUHAN, Oct. 29 (Xinhua) -- Metro Line 12 in Wuhan, the capital of central China's Hubei Province, became fully operational on Thursday, making it China's longest metro loop line, according to the China Association of Metros.

Stretching 59.9 kilometers and serving 37 underground stations across seven urban districts of Wuhan, the line connects the Wuchang and Hankou railway hubs and offers transfers to 18 existing and planned lines. A full loop takes about 96 minutes.

The line opened in two phases. The first phase, 35.3 kilometers long, entered service on May 1 this year. With the second phase now operational, Wuhan Metro's operational length exceeds 581 kilometers, roughly the driving distance between Berlin and Munich or between Rome and Milan.

Wuhan, known as the "river city," has complex geological and hydrological conditions, which posed multiple challenges during construction. The line passes under the Yangtze River twice and the Hanjiang River once. Construction teams overcame a series of technical difficulties, including high water pressure and composite strata.

One cross-river tunnel, in particular, is approximately 4 kilometers long, with its lowest point 71.4 meters below the Yangtze River surface. The project has provided valuable experience for building super-large-diameter cross-river tunnels in China.

Wuhan, home to over 13.86 million permanent residents, is a key transport hub in China and a core city of the Yangtze River Economic Belt. The opening of Metro Line 12 is expected to further facilitate cross-river commuting.

China has issued a plan to comprehensively advance the high-quality development of integrated transport services during the 15th Five-Year Plan period (2026-2030), the Ministry of Transport announced in July this year. The plan aims to basically establish a modern integrated transport service system by 2030.

Under the plan, China will improve connections among different modes of transport, make passenger transfers more convenient and enhance freight logistics services.