Line 11 of the Shenzhen Metro opened on 28 June 2016. Line 11 has a length of 53.5 km (33.2 mi) and a total of 19 stations. It connects the CBDs of Futian, Nanshan and Qianhai to Shenzhen Bao'an International Airport and onward to Fuyong, Shajing and Songgang suburban areas. It serves as both a regional express line from the west coast of Shenzhen to the city core area and an airport rail link. Compared with the other lines of Shenzhen Metro, Line 11 has a longer spacing between stops for a higher speed service. Trains of Line 11 were designed to run at 120 km/h (75 mph), up to 50% faster than other lines, but currently limited to 80 km/h (50 mph) in some sections for infrastructure, tunnel wind pressure, track geometry issues and noise reasons. Construction of Line 11 started in April 2012 and test running begun at the end of March 2016. Trains ran at a 4-minute frequency between Futian and Airport North, 8-minute frequency for full length trains during morning rush hours, 5-minute interval for full length during evening rush hours, and 6-minute interval for non-peak hours. Increasing demand on Line 11 led to Shenzhen Metro purchasing more trains in 2020, reducing headways to as low as every 2 min 10 seconds. Currently it takes slightly more than half an hour to travel from Futian to the Airport.