Tram

a tram

A tram is a kind of bus but runs on rails and uses overhead electric wires. It runs on roads like buses. Trams are mainly in big cities. Trams can carry more people than busses, so it makes it useful if lots of people go the same route. It also makes less pollution.

A main disadvantage is that trams on the same line can't overtake each other. If, for example, three trams are traveling on the same line, the first tram gets more people because it's first, by the time the next trams arrive there are fewer people so less time to wait a tram stop. When they catch up with the other tram they have to wait as all the people get into the first tram.

In China there are double decker trams.