W class trams were introduced to Melbourne, Australia in 1923 as a new standard design. They had a dual bogie layout and were characterised by ingeniously simple, rugged design, and fine craftsmanship (particularly the older models). The W Class was the mainstay of Melbourne's tramways system for 60 years.

The original and most numerous W2 variant was supplemented in the late 1930s by 120 W5 (or "Clyde") class trams with wider cabins, and more powerful motors - which were notorious for being difficult to drive smoothly. The W6 followed on: it was to become the most popular W class tram with crews and pasengers alike: fast, smooth and comfortable - at least by W Class standards! Construction came to a halt for some years and the final 40 W Class trams did not emerge from the Preston Workshops until 1956, when the need to provide something more capable of dealing with Olympic Games crowds than Bourke Street's buses prompted the last expansion of the network. The W7 Class with its pneumatic sliding doors (later retrofitted to most W5 and W6 trams too) and softer suspension was popular with passengers but feared by crews, as the braking system - not a strong point in any W Class variant - was never really adequate.

From 1956 on, Melbourne's tramways system was allowed to deteriorate. In the golden era of the 1920s and 1930s, loadings were heavy, a tram conductor earned more than a schoolteacher or a policeman, and the slightest scratch or spot of dirt on the rolling stock was dealt with immediately. The Melbourne and Metropolitan Tramways Board (M&MTB) was so profitable that it had to invent ways to spend money, notably by constructing the enormous Wattle Park gardens and the Vimy House private hospital for Tramways staff. With the expansion of the city's outer suburbs during the post-war baby boom and the ever-increasng role of the motor car, the M&MTB was neglected by a succession of state governments, largely in the belief that public transport was a thing of the past. No new lines were constructed, staff morale gradually fell, and the rolling stock was allowed to decay. The prolonged survival of the W Class fleet was testament to the original sound, practical design and solid construction.

The development of new rolling stock to replace the W Class finally began in 1975 with a complex and expensive Swedish design that was ill-suited to Melbourne's hot summers and heavy loadings. Although the Z Class was improved over time with the revised Z2 and Z3 variants, it was not a success, and it was not until the 1990s that the W Class was finally retired from regular commuter duty. Some can still be seen running from time to time, with the oldest examples apparently from 1938. Some history of many of the decommissioned trams has been documented. For example, it is claimed that Elton John has possession of Number 520 in Windsor, UK. A free city circle line operates using them to the delight of many tourists and a few have been converted into upmarket mobile resturants which cruise the suburbs in the evening.

The tram lines generally radiate outwards from the city centre of Melbourne, with several tram depots located in inner Melbourne suburbs. Until quite recently trams were manned by a tram conductor, whom would collect fares and issue tickets which could be utilised on other forms of transport throughout the Melbourne transport system. However, with Melbourne moving towards an automated ticketing system, ticketing machines have been implemented across many trams, with the conductors no longer being required. This does not translate into free travel though, as Melbourne Metropolitian Ticketing Inspectors ("metcops") being notorious for issuing fines in a very aggressive manner - fines are immediate and currently stand at AUS$100.