Line 4 is a line of Suzhou Rail Transit. It runs in a north-south alignment from Longdaobang station in Xiangcheng District's the northern suburbs, to the canal town of Tongli in Wujiang District in the south and Muli in the southwest. The line is 52.8 km long with 38 stations, which consists of a 41.5 kilometer long main line with 30 stations and a branch line.

Line 2 is a north-south line of Suzhou Rail Transit. It passes through five districts of Suzhou, and has 22 stations, 17 underground and 5 elevated. It began operations on December 28, 2013.