The Beijing Subway is a rapid transit rail network that serves the urban and suburban districts of Beijing municipality. The network has 18 lines, 334 stations and of track in operation, and is the second longest subway system in the world after the Shanghai Metro. The subway is the world's busiest in annual ridership, with 3.41 billion trips delivered in 2014, averaging 9.2786 million per day, with peak single-day ridership reaching 11.5595 million.