The Bannan or Blue line (code BL) is a metro line of Taipei Metro in Taipei, Taiwan, with a total of 23 stations serving the districts of Nangang, Xinyi, Daan, Zhongshan, Wanhua, Banqiao and Tucheng. The line's name is a portmanteau of Banqiao and Nangang.
The entire line runs underground. The excavation of tunnels using the cut-and-cover method resulted in large scale detouring of road traffic. Because of that, the line runs beneath existing roads and totals 28.3 km (17.6 mi).
Service on this line is divided into a full-length service from Taipei Nangang Exhibition Center to Dingpu, as well as a shorter service from Kunyang to Far Eastern Hospital.
Due to Taipei City Hall being at the centre of the Taipei 101 New Year's festivities, intervals between trains can be reduced to a minimum of 135 seconds, transporting up to 39,000 passengers per hour.[1] This results in an average of about 27 trains per hour on the line during peak hours.
21 May 2014: The 2014 Taipei Metro attack occurs between Longshan Temple and Jiangzicui when 21-year-old university student Cheng Chieh attacked passengers with a fruit knife, leading to 4 deaths and 24 injuries.
28 September 2018: Half-height platform edge doors are installed in Tucheng, making all stations on this line and entire Taipei Metro system have some form of platform doors.