Line 21 of the Shenzhen Metro is an express line under planning, which will connect across Shenzhen through the districts of Nanshan, Longhua and Longgang for 66 kilometers and 26 stations.[1] The first phase of Line 21 originally entered Phase V planning in September 2022, and will run from Aobei to Longyuan in Longgang District, with 6 stations and 12.5 kilometers of track,[2][3] however planning has been put on hold since 31 March 2023. The line is proposed to use 8 car type A trains.[4]
