The Rio de Janeiro Metro (Portuguese: Metrô do Rio, commonly called Metrô) is a mass-transit underground railway network that serves the city of Rio de Janeiro, Brazil. Founded in 1979 with five stations operating on one line, it now covers 47 km (29 mi) divided into two lines and 35 stations. It is the second largest metro system in Brazil after the São Paulo Metro.
The system currently consists of two lines, with another under construction:
Line 1 (orange line), which serves downtown Rio, touristic areas in the South Zone, and several neighborhoods in the North Zone. It is a semi-circular line, and is fully underground. It runs from Saens Peña to Ipanema/General Osório.
Line 2 (green line), which serves working-class residential neighbourhoods extending toward the north. It is a diagonal line, and almost completely over ground (mostly at graded and partly elevated). This line started as a light rail, but for increasing commuters, it gradually changed to metro. Due to its origin as light rail, it is at-grade except for Estácio station (the former connection station between lines 1 and 2), which is underground and Cidade Nova station, which is elevated.
Line 4 (silver line), to be completed in 2016, will finally reach the Barra da Tijuca neighbourhood in the West Zone, passing under São Conrado and Rocinha. All stations will be underground, but there will be a bridge leading to a tunnel inside a mountain.