The W-class trams are a family of electric trams built by the Melbourne & Metropolitan Tramways Board (MMTB) between 1923 and 1956. Over the 33 years of production, 752 vehicles spanning 12 sub-classes were constructed, the majority at the MMTB's Preston Workshops. A small fleet continue to operate on the tramway network of Melbourne, Australia, where they are used on the City Circle tourist route. The W-class tram is a cultural icon to Melbourne: those that remain in the city are classified by the National Trust of Australia. As well as Melbourne, W-class trams operate on tourist and heritage systems across the world. A number of older variants have been withdrawn from service and later sent to cities such as Copenhagen, San Francisco, Savannah and Seattle, and by private enthusiasts. In 2018, 134 W-class trams were offered to the Australian public for new uses. As of December 2021, only 13 W class trams remain in service in Melbourne, all of which are W8 trams operating on the City Circle tram route. History W-class trams were introduced to Melbourne in 1923 as a new standard design. They had a dual bogie layout and were characterised by a substantial timber frame supplanted by a steel underframe, a simple rugged design, and fine craftsmanship (particularly the older models). The W class was the mainstay of Melbourne's tramways system for 60 years. A total of 752 trams of all variants were built. The original variant (W) was a typical Drop-centre design tram, which was also used in Adelaide, Brisbane, Sydney, and later Bendigo, Ballarat and Geelong following movements of earlier Melbourne trams. The W1 was created with no centre doors, and changed to the W2 design, which all earlier Ws were upgraded to. A handful were upgraded to the SW2 design with sliding doors, which were followed by the unsuccessful W3 and W4 designs. All were supplemented in the late 1930s by 120 W5 (or "Clyde") class trams with wider cabins, and more powerful motors. However, they were notorious for being difficult to drive smoothly. After this came the SW5, initially only the last ten W5 trams fitted with sliding doors before entering service, but by the 1990s the majority of the W5 fleet, having been upgraded. The SW6 followed on, and became the most popular W-class tram with crews and passengers alike, because they were fast, smooth and comfortable, compared with earlier W