Port Arthur (now Thunder Bay) was the first municipality in Canada to establish its own street car system in 1892. (Fort William had a private streetcar in 1891). So, Thunder Bay Transit (which the agency was renamed as when it absorbed Fort William Transit during our 1970 amalgamation) is the oldest municipally operated public transit agency in Canada.
The system was unified and split up several times over the years, with Fort William Street Railway being separated and absorbed various times by Port Arthur Street Railway, later Port Arthur Public Utilities Commission. The streetcars were powered by a dam build in the north end of the city, which created the lake that separated Current River from the urban fabric. Electric trolley buses were introduced in the 1930s, gas buses shortly after. The streetcars were last used in 1948. In 1972, the last of the electric trolleys was taken out of service. The city has two electric buses from Vancouver (but the same model as we used here, and like St. Louis our transit system's vehicles were built at a plant located in the city), which will be put on display at some location in the near future.
The main streetcar line has been called The Mainline since the 1800s, and it still operates roughly along that route today. It's the only bus route we never have to change when we reconfigure our transit system, since it is basically already in its most optimal layout. It only gets minor changes on its suburban ends.