Europe has an extensive number of tramway networks. Some of these networks have been upgraded to light rail standards, called Stadtbahn in Germany, premetros in Belgium, sneltram in the Netherlands, elétrico in Portugal and fast trams in some other countries. Overview The introduction of trams in all the major cities of the late 19th century forced users and non-users alike to adjust to this intrusive, but clean and efficient form of transportation. Many early trams were horse-drawn, but electric trams followed. By the mid-1910s, the urban population were fully accustomed to trams as a fashionable mode of transport for work and leisure, and as a very positive and visual sign of the prosperity and prestige of the city. Visitors from the farms, villages and small towns sometimes made a trip on the tram a high priority when they came to the big city. A number of cities have retained - but also expanded - their original 19th century tram network, notably Warsaw (1866), Lisbon (1872), Gothenburg (1879), Budapest (1887), Prague (1891), Kyiv (1892), Milan and Genoa (1893), Rome, Bucharest and Belgrade (1894), Porto (1895), Vienna (1897), Helsinki (1899), and Gdańsk and Sarajevo (1895). After World War 2, trams were seen as advantageous in many countries because, unlike buses, they did not use scarce petrol resources. However many tramways closed in the mid 20th century, as they were seen as less effective in terms of costs and use of the roadway than other forms of street transport. However, in recent decades tram networks in many countries in Europe have grown considerably. The Netherlands, which already makes extensive use of trams, has plans to expand tram services to two additional cities. In Germany, many cities retain their original tram networks. In some places, tram networks have been added or expanded through the introduction of hybrid tram-train or stadtbahn systems which may combine standard railway, on-street and underground operations. Notable examples are the systems in Cologne and Karlsruhe. In Frankfurt-am-Main, many tram lines were transferred to U-Bahn operation. In the United Kingdom, investment in public transport in the late 1980s turned to light rail as an alternative to more costly underground railway solutions, with the opening of the Tyne & Wear Metro in Newcastle (1980) and the Docklands Light Railway in London (1987) systems. However, the first British city to reintroduce on-street trams was Manchester, with the opening of its Metrolink network in