Steam trams first ran in Sydney from 1879, with the last running in 1937. Running through city streets, any emissions from them were very apparent and hence a boiler fuel such as the relatively ‘smokeless’ coke was popular. Illawarra coke was one such supply.
The Steam Trams in Sydney comprised a Baldwin locomotive hauling one or more trailers of either single deck or double deck construction.(https://en.wikipedia.org/wiki/Trams_in_Sydney 071020)

Courtesy State Archives and Records Authority of New South Wales
under Creative Commons Attribution 2.0 Generic license
In 1879 to facilitate travel to the International Exhibition, to be held in the Garden Palace in the Botanic Gardens, a steam tramline from the railway terminus to Hunter Street via Elizabeth Street was constructed as a stop-gap measure. The new steam tramway was an immediate success. Nearly half a million passengers were conveyed, an average of more than 4,000 per day. Further, the return on the capital invested was high around 33 per cent.
In light of this success, a bill authorising the NSW Government to construct tramways throughout the city and its suburbs was given assent in April 1880.
This began an era of rapid growth in the tramway network-from 2.5 kilometres in 1879 to almost 50 kilometres in 1884. The peak of the service was reached during 1894, when the length of the tramway reached 40 miles (64.7 km) when there were over 100 steam trams in service. Intense competition from horse buses saw trams racing buses along various routes.
While the new steam trams were speedy, economical and reliable, they also had environmental impacts, causing high levels of dust, noise and smoke in the city street. (http://dictionaryofsydney.org/entry/trams 071020)
Steam trams of the type represented in this collection of moveable heritage were particular to NSW. Steam tramways featured in Sydney and immediate suburbs (1879-1907), together with the Parramatta-Castle Hill (1902-1923/26), Manly-Brookvale (1903-1911), Arncliffe-Bexley (1909-1926), Cronulla-Sutherland (1909-1932), Kogarah-Sans Souci (1887-1937), Ashfield-Mortlake (1891-1901-1912). Systems also evolved in Newcastle and suburbs, Maitland (1909-1926). Plans were drawn up for systems in Wollongong and Lismore but did not eventuate.
Postal services were improved, including the provision of mobile post boxes on some trams. The expression “Shooting through like a Bondi tram,” referred to the express mail services using the steam tram to Bondi Beach. On the Newcastle and Sutherland lines, a hearse car was attached on occasion to enable interments at Sandgate and Woronora cemeteries.
The steam tram systems in Sydney and Newcastle formed the foundation of the electric tram systems that succeeded them in them in the twentieth century. In other centres they were succeeded by bus transport. In its heyday in the 1920s the NSW steam tramway network was the biggest in Australia and the second largest system in the world. It was an important element in the development of public street transport in NSW.
(NSW Office of Environment & Heritage https://www.environment.nsw.gov.au/heritageapp/ViewHeritageItemDetails.aspx?ID=5062526 071020)