Metro lines 16 (above) and 12 open Sunday to waiting passengers. The passenger volume of Line 16 was 36 percent higher than Line 12 as of 1 pm. The opening of the lines gave Shanghai the most extensive subway system in the world. Photo: Yang Hui/GT

With the opening of metro lines 12 and 16 Sunday, Shanghai now has the most extensive subway system in the world, local media reported.

The city's subway system has more than 567 kilometers of track and 331 stations, according to Shanghai Shentong Metro Group, the city's subway operator.

However, just because Shanghai has the world's longest network of metro lines doesn't mean it's a leader in the development of urban transportation, said Sun Zhang, a professor at the Institute of Railway and Urban Mass Transit at Tongji University.

Sun suggested that the city would be better off with more types of public transportation, such as rail lines, especially outside the city center.

Tokyo's subway system has 290 kilometers of metro lines downtown and more than 1,846 kilometers of railway lines in the suburbs, according to a report in the Oriental Morning Post. New York has 370 kilometers of metro lines downtown, but there are 3,630 kilometers of railway lines in the suburbs.

Shanghai's two new lines currently have 26 stations under operation. Line 12 runs from Tiantong Road Station in Hongkou district to Jinhai Road Station in Pudong New Area. Passengers can transfer to metro lines 4, 6 and 10 at Dalian Road, Jufeng Road and Tiantong Road stations, respectively, according to Shanghai Shentong Metro Group.

Line 16 runs from Luoshan Road Station to Dishui Lake Station in Pudong New Area. Passengers can transfer to metro Line 11 at Luoshan Road Station. The line operates two types of trains. One type stops at every station on the line, just like most other subway lines.

The second type of train only stops at four of the line's 11 stations during the morning and evening rush hours: the two stations at either end of the line, plus Xinchang and Huinan stations.

The purpose of the second type of train is to make it faster for passengers to travel from one end of the line to the other.

As of 1 pm Sunday, more than 25,000 passengers have ridden Line 12 and more than 34,000 passengers have taken Line 16, according to Shanghai Shentong's microblog.

Shanghai has plans to further extend the metro system. Construction of the third phase of metro Line 13, which runs from Middle Huaxia Road Station to Zhangjiang Road Station, will begin next year.