Gothenburg tram network  The Gothenburg tramway network () is part of the public transport system organised by Göteborgs Spårvägar, controlled by Västtrafik in the Swedish city of Gothenburg. The system's approximately of single track — making it the largest tram network in Northern Europe — is used by around 200 trams , which serve twelve day-time and five night-time lines with a combined line length of 190 km. These figures are expected to increase when the second stage of "Kringen" (short for "Kollektivringen", the public transport ring) is finished. The trams perform about 2,000 trips and cover 30,000 km per day. In 2018, 131 million journeys were made (with changes counting as a new journey). The first tram line in Gothenburg was started in 1879 by the English company Gothenburg Tramway Ltd. This was a horse-drawn tramway, which stretched from Brunnsparken to Stigbergsliden. The city of Gothenburg bought the tramway in 1900, and introduced electrically powered trams only two years later when Sigfrid Edström led the electrification of the trams. During the next 40 years, the tram system was heavily expanded, reaching outside the city borders by 1907, and Hisingen in 1940. In the 1960s, plans for converting the tram system to an underground rapid transit system were created, and the new tram sections to the Tynnered, Angered, Bergsjön and Länsmansgården suburbs were built free from level crossings and partly in tunnels to make a future conversion to underground standards easier. However, after further investigation, it was concluded that it would be too expensive to dig the necessary tunnels under the city centre, as the foundation of the city is partially made up of clay. When Sweden's switch to right-hand traffic in 1967 made existing unidirectional trams obsolete, Gothenburg was one of only two cities in Sweden to maintain its city-centre tramway, the other such network to survive being the Norrköping tramway. The expansion of the net through the "Kringen" is gradually and step by step creating a tramway ring around the city centre. In 1999 the first step was started, which most notably included the 1050 m long Chalmers tunnel which was opened for traffic in 2002, connecting the Chalmers station with the Korsvägen hub.