Planning for a metro system began in the early 2000s, in the meantime the mostly elevated Xiamen BRT opened in 2008.On 8 October 2016, the National Development and Reform Commission approved phase II of the Xiamen Urban Rail Transit Construction Plan (2016–2022).The approved phase I metro expansion plan includes three lines (1, 2, 3) with 62 stations, 75.3 kilometres (46.8 mi) in length.[16] In addition, a regional rail system consisting of two lines (Quanzhou–Xiamen–Zhangzhou and Zhangzhou–Gangwei–Xiamen) and 263 kilometres (163 mi) in length was also approved.[17][18] Line 1, with 24 stations, 30.3 kilometres (18.83 mi) length, 50 min duration of trip and 20.39 billion yuan cost of construction, was opened on 31 December 2017.[29][30] The total length of Line 9 Phase 1 is 30.7 kilometres (19.08 mi) kilometers with 17 stations, and runs completely underground.[40] A long term plan, Line 10, spanning 40.4 kilometers (25.1 mi) with 31 stations, is proposed to primarily be reconstructed from the Xiamen BRT.[41] In addition, there are plans to connect the Xiamen Metro with neighboring cities of Zhangzhou and Quanzhou using a new express subway Line R1.