Line 13 of the Beijing Subway () is a metro line that serves the northern suburbs of Beijing. On a map, Line 13's route is shaped like an inverted U that arcs north of the city and connects residential suburbs in Haidian, Changping and Chaoyang Districts with the 2nd Ring Road and Line 2 at Xizhimen and Dongzhimen. With the exception of and a tunnel between Xi'erqi and Longze, all of Line 13's tracks and stations are located on the surface or elevated above ground. The line is and 16 of its 17 stations are on the surface. Line 13's color is yellow. During rush hour, the section between Xizhimen and Wudaokou Stations was reported in 2013 to be the second most congested section in the Beijing subway network, operating at 130% capacity. Fare Starting fare of RMB(¥) 3.00 that increases according to the distance fare scheme introduced in December 2014. Regular subway users can use a Yikatong card, which offers even cheaper journeys, as well as mobile phone apps, which deploy payment via a QR code. Hours of operation The first trains depart from and at 5:35am. The last trains to go the full-distance and reach the other terminus depart from Xizhimen and Dongzhimen at 10:42pm. In addition, Line 13 offers later night trains from either terminus that travel half of the full route. The last train to leave Xizhimen, departs at 11:45pm and ends its journey at Huilongguan at 12:09am. The last train to leave Dongzhimen, departs at 11:45pm and ends its journey at Huoying at 12:09am. For the official timetable, see. The frequency of trains on Line 13 vary from 3.5 minutes per train during the morning rush hour (6:20am – 9:40am) to 5 minutes per train during the evening rush hour (4:40pm – 8:40pm) to 10-11.5 minutes per train after 10:50pm. For full listing of train frequency, see. Route Line 13's route is shaped like a horseshoe over northern Beijing. From in Xicheng District, Line 13 heads north, running alongside the Beijing-Baotou Railway into Haidian. After three stops in the bustling university district -- , (transfer to Line 10) and —Line 13 leaves the 5th Ring Road and enters the suburbs of northern Haidian. At , Line 13 meets the Changping Line, and turns east, following the southern edge of Changping District for three stops (, , and ), before turning to the southeast. It enters