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.

Preston Workshops is the heavy maintenance facility for the Melbourne tram network. The workshop is located on a block surrounded by Miller Street, St Georges Road, Oakover Road and the Mernda railway line in Preston, a suburb in Melbourne, Victoria, Australia. Following a major redevelopment in April 2016, it also became an operational depot under the name New Preston Depot, taking over from East Preston.