In Porto, like in most cities before electric trams were introduced, horse trams provided the urban public transport, although in Porto more often mules were used. Steam trams were used in many cities too, most on busy suburban routes. Porto was one of the cities in Europe using steam locomotives for trams. This page is about the steam trams of Porto that operated in the city for 36 years. This page is about the history of the steam tramline and the locomotives used, there is a separate page about the tram vehicles that were hauled not only by the locomotives, but also by mules and electric trams.