In the early days of the tram, by no means every system was electrified.
The first British tramway was horsepowered. It opened in 1860 in Birkenhead, built by an American named George Train. A single horse was sufficient to pull each carriage along the rails that were set into the surface of the town's fairly level streets. Enthusiasm for this new means of transport spread rapidly to other towns and cities so that, 25 years later, there were some 700 miles of horsepowered tramways around the country, with more than 3000 trams being pulled by 25,000 horses. Some operators were more efficient than others. When the Newport system came under new ownership in 1902, its accounts declared 137 horses to be in use.
On investigation, it was found that 20 of these were dead and another 20 had been sent to kennels for dog-food. The accounts also showed an annual profit of eight shillings (40p) from the sale of manure.
The success of steam power on the railways led to its use on some tramway systems. Small steam locomotives were built, fitted with safety "skirts" round their wheels and condensing apparatus to consume their own steam. But they proved unreliable, unpopular and very smoky.
A visitor to Edinburgh in the early years of the 20th century asked his hotel chambermaid to explain a continuous rumbling that could be heard throughout the city. "Och, it's the cars," she replied - by which she meant the trams.
As the city's streets were too hilly for horse-drawn trams, the council had opted for cable cars. Hefty cables, many miles long, rumbled continuously in below-surface conduits between the tram lines. To start a tram, the driver operated the jaws of a grip beneath his car. Clamped to the cable, the tram lurched forward - and stopped when the driver released the grip.
Junctions were amazingly complex and curves presented special problems. Not surprisingly, most systems soon converted to other means of propulsion, but cable power is still in use on the Great Orme Tramway at Llandudno in North Wales and in San Francisco. (The overhead trolley on some cable cars does not supply power but allows the driver to communicate with the winding house from where the cables are powered.)