Line 4 is a line of the Suzhou Metro. It runs in a northâÂÂsouth alignment from Longdaobang station in Xiangcheng District's the northern suburbs, to the canal town of Tongli in Wujiang District in the south. The line is 41.5 km long with 31 stations.
Until October 2024 there was a 11.3 km long branch line with 7 stations. This branch line was later transferred to line 7.
Groundbreaking occurred on December 31, 2010 in Wujiang, and the line was constructed between 2012 and 2016. Operations started on April 15, 2017.
Trains are run in six-car formations, and have a maximum speed of 80 km/h.