Australasia
In Australasia, trams are used extensively only in Melbourne, and to a lesser extent, Adelaide, all other major cities having largely dismantled their networks by the 1970s. Sydney reintroduced its tram in 1997 as a modern system (Metro Light Rail), while Ballarat, Bendigo, Christchurch and Perth reintroduced their trams as heritage systems.
A distinctive feature of many Australasian trams was the early use of a lowered central section between bogies (wheel-sets). This was intended to make passenger access easier, by reducing the number of steps required to reach the inside of the vehicle. It is believed that the design first originated in Christchurch in the first decade of the 20th century. Cars with this design feature were frequently referred to as "drop-centres".
The trams made by Boon & Co of Christchurch, New Zealand in 1906–07 for use in Christchurch may have been the first with this feature; they were referred to as drop-centres or Boon cars. Trams for Christchurch and Wellington built in the 1920s with an enclosed section at each end and an open-sided middle section were also known as Boon cars, but did not have the drop-centre.
Read more about this topic: Tram And Light-rail Transit Systems