Short answers, pulled from the story.
Tram and streetcar refer to the same type of vehicle. "Streetcar" is the preferred term in English Canada and the western United States, while "trolley" is favored in the eastern US. The word tram derives from the Scots tram, originally referring to mine wagons and their tracks.
The world's first electric tram line was invented and tested by Fyodor Pirotsky in Sestroretsk near Saint Petersburg in 1875. The first electric tramway used for permanent commercial service was the Gross-Lichterfelde tramway near Berlin, opened in 1881 and built by Werner von Siemens.
Volk's Electric Railway in Brighton, UK, opened in 1883, is the oldest operating electric tramway in the world. It runs two kilometers along the seafront and was re-gauged in 1884.
Melbourne, Australia, is generally recognized as having the largest urban tram network in the world. As of 2016, the Melbourne system had 256 km of route, ahead of Kyiv at 231 km and Saint Petersburg at 205.5 km.
Improvements in buses and the growth of automobile use led many cities to replace their tram networks from the mid-20th century onward. The General Motors streetcar conspiracy is cited as a case study in the decline of trams in the United States. Most Australian cities also abandoned trams after World War II, with Melbourne being the main exception.
Trams and light rail systems carry 13.5 billion passengers a year, representing 3 percent of all public transport passengers globally. The highest-volume individual systems are Budapest with 396 million passengers a year, Prague with 372 million, and Bucharest with 322 million.