Line 4 of the Chengdu Metro (Chinese: 成都地铁4号线; pinyin: Chéngdū Dìtiě Sì Hào Xiàn) is the third line to enter revenue service on the metro network in Chengdu, Sichuan. Line 4 runs in an east-west direction, stretching from Wansheng in Wenjiang to Xihe in the Longquanyi.[2] The first phase started construction on July 22, 2011, and began operation on 26 December 2015.[3] Testing began on the east of west extensions of Line 4 as part of Phase II expansion on December 10, 2016.[4]