CRT Line 6 (and the branch line branded as International Expo line) is the second heavy railsubway line in Chongqing, as well as being the longest rapid transit line in China, at 85.6 km (53.19 mi) long. It opened with provisional revenue service on September 28, 2012, and connects Nan'an, Yuzhong, and Jiangbei districts in central Chongqing.