Streetcar
Introduction
Streetcars are transit vehicles that operate using steel wheels on steel rails. They are capable of operating in either mixed traffic or on their own right-of-way, and are generally powered by an overhead electrical power supply, although there are systems that use a low-mounted third rail or even onboard diesel power plants. They tend to be smaller and lighter than "heavy rail" subway vehicles, but in many cases are able to be coupled in multiple to increase their capacity. The majority of the streetcars in the world are single deckers although there are at least two systems in the world that still operate double decker streetcars.
Advantages and Disadvantages of Streetcars
The advantages of streetcars are that they often do not produce any street-level pollution - because many are electrically powered, pollution is able to be monitored at a single source. They are also frequently larger than buses, and this coupled with their ability to couple to each other means that one operator is capable of moving far larger numbers of people than that same operator with a bus. Studies have shown as well that more people are inclined to use a streetcar line than a bus line, as once the transit property has invested in the infrastructure there is a sense of "permanence" with the line.
The disadvantages of streetcars are that streetcar systems are expensive to buy and build - fewer streetcars are built around the world than buses, and quite a bit of infrastructure is necessary to allow a line to operate, far more so than necessary than to operate a bus line. At lower frequencies and passenger loads, operating costs can also be higher than with buses.
Agencies with Streetcar Systems
Current
Canada 
- Ion - Kitchener-Waterloo Region, ON
- Toronto Transit Commission - Toronto, ON
United States 
Incomplete.
Heritage Railways
- Canadian Railway Museum - Montréal, QC
- Edmonton Radial Railway Society - Edmonton, AB
- Halton County Radial Railway - Milton, ON
- Heritage Park Historical Village - Calgary, AB
- Nelson Electric Tramway Society - Nelson, BC
Future
- Calgary Transit - Calgary, AB (planned)
- TransEd - Edmonton, AB (under construction)
Past
Incomplete.
Canada
- Calgary Municipal Railway - Calgary, AB (1908-1950)
- Edmonton Radial Railway - Edmonton, AB (1908-1951)
- Lake Louise Tramway - Lake Louise, AB (1912-1930)
- Lethbridge Municipal Railway - Lethbridge, AB (1912-1947)
- Moose Jaw Electric Railway - Moose Jaw, SK (1911-1932)
- Ottawa Electric Railway (1870-1948)
- Ottawa Transportation Commission (1948-1959)
- Saskatoon Municipal Railway - Saskatoon, SK (1913-1951)
- Regina Municipal Railway - Regina, SK (1911-1950)
- TRAMS - Vancouver, BC (heritage railway, closed 2012)
- Whitehorse Trolley - Whitehorse, YT (heritage railway, closed 2018)