Stockholm has an extensive public transport system. It consists of the Stockholm Metro (), which consist of three color-coded main systems (green, red and blue) with seven lines (10, 11, 13, 14, 17, 18, 19); the Stockholm commuter rail () which runs on the state-owned railroads on six lines (40, 41, 42, 43, 44, 48); four light rail/tramway lines (7, 12, 21, and 22); the 891 mm narrow-gauge railway Roslagsbanan, on three lines (27, 28, 29) in the northeastern part; the local railway Saltsjöbanan, on two lines (25, 26) in the southeastern part; a large number of bus lines, and the inner-city Djurgården ferry. The overwhelming majority of the land-based public transport in Stockholm County (save for the airport buses/airport express trains and other few commercially viable bus lines) is organized under the common umbrella of Storstockholms Lokaltrafik (SL), an aktiebolag wholly owned by Stockholm County Council. Since the 1990s, the operation and maintenance of the SL public transport services are contracted out to independent companies bidding for contracts, such as MTR, which operate the Metro. The archipelago boat traffic is handled by Waxholmsbolaget, which is also wholly owned by the County Council.