A The tram was once thought to belong to the past. In the middle of the twentieth century many European and American cities removed their tram lines to make room for cars and buses, and the vehicles that remained were often old and slow. By the 1970s trams had almost disappeared from many places.
B In recent decades the tram has returned. Cities that had suffered from traffic jams and polluted air looked again at a form of transport that runs on electricity and carries many passengers on a single line. Modern trams are quiet, accessible to wheelchairs and prams, and can be linked to other services such as buses and trains.
C Building a tram line is expensive and disruptive. Roads must be dug up, utilities moved and shops can lose customers while work is carried out. Some residents complain about the noise of construction, and not every project has been completed on time or on budget. Supporters answer that a line, once built, can last for many decades.
D Evidence from cities that have opened new lines suggests that tram routes can encourage people to leave their cars at home, and that shops and housing near stops often become more valuable. Planners warn, however, that a tram works best in busy corridors. In a thinly populated area, a bus can be a cheaper and more flexible choice.
