structural:summarization, linguistic:paraphrasing
Subway

Xiamen subway initiated construction on 1 April 2014 and was put into experimental operation on 31 December 2017. According to Xiamen's rail traffic planning approved by the central government, the city has three metro lines by 25 June 2021 and will also accelerate the construction of Metro Line 4 and 6, with a total length of 233 kilometers. The city will witness the rapid development of its subway traffic network. The Metro Line 1, 2 and 3 has currently started operation.