The Z-class are single-unit bogie trams that operate on the Melbourne tram network. Between 1975 and 1983, 230 trams spanning three sub-classes were built by Comeng, Dandenong. The design was based on two similar Gothenburg tram models, and a prototype built by the Melbourne & Metropolitan Tramways Board. While the Z1 and Z2-class trams were very similar, the Z3-class had significant design changes.