Uni-directional Vehicle

A uni-directional vehicle is a

vehicle A vehicle () is a machine designed for self-propulsion, usually to transport people, cargo, or both. The term "vehicle" typically refers to land vehicles such as human-powered land vehicle, human-powered vehicles (e.g. bicycles, tricycles, velo ...

that is normally designed to operate only in the forward direction. While the vast majority of

road vehicle A motor vehicle, also known as a motorized vehicle, automotive vehicle, automobile, or road vehicle, is a self-propelled land vehicle, commonly wheeled, that does not operate on rails (such as trains or trams), does not fly (such as airplanes ...

s are like this, the term generally refers to a

train A train (from Old French , from Latin">-4; we might wonder whether there's a point at which it's appropriate to talk of the beginnings of French, that is, when it wa ... , from Latin , "to pull, to draw") is a series of connected vehicles th ...

tram A tram (also known as a streetcar or trolley in Canada and the United States) is an urban rail transit in which Rolling stock, vehicles, whether individual railcars or multiple-unit trains, run on tramway tracks on urban public streets; some ...

with a distinguishable front and rear end and a single operating cab at the front end. These vehicles often have the capability to operate in reverse, though such operations are limited to low speeds and short distances, such as shunting. Uni-directional vehicles commonly have entry and exit

door A door is a hinged or otherwise movable barrier that allows ingress (entry) into and egress (exit) from an enclosure. The created opening in the wall is a ''doorway'' or ''portal''. A door's essential and primary purpose is to provide securit ...

s on only one side of the vehicle (usually the

sidewalk A sidewalk (North American English), pavement (British English, South African English), or footpath (Hiberno-English, Irish English, Indian English, Australian English, New Zealand English) is a path along the side of a road. Usually constr ...

side), although some are equipped with doors on both sides, or operate in opposing traffic flow, to facilitate the use of

island platform An island platform (also center platform (American English) or centre platform (British English)) is a station layout arrangement where a single platform is positioned between two tracks within a railway station, tram stop or transitway inte ...

s. Having doors on only one side allows for an increase in seating on board the vehicle, compared to

bi-directional vehicle A bi-directional vehicle is a vehicle that can be driven in either direction, forwards or backwards. Usually, the term refers to rail vehicles, such as trains or trams, and some airside transfer buses, that are equipped with driver's cabs at ...

s which have doors on both sides. Because a uni-directional vehicle can only travel in one direction they require special infrastructure for turning around at a

terminal station A train station, railroad station, or railway station is a railway facility where trains stop to load or unload passengers, freight, or both. It generally consists of at least one platform, one track, and a station building providing such ...

. This is usually a

balloon loop A balloon loop, turning loop, or reversing loop ( North American Terminology) allows a rail vehicle or train to reverse direction without having to shunt or stop. Balloon loops can be useful for passenger trains and unit freight trains. Bal ...

on tram systems, which mainline railways tend to use a

triangle junction In railroad structures and rail terminology, a wye (like the'' 'Y' ''glyph) or triangular junction (often shortened to just triangle) is a triangular joining arrangement of three rail lines with a railroad switch (set of points) at each corner ...

turntable A phonograph, later called a gramophone, and since the 1940s a record player, or more recently a turntable, is a device for the mechanical and analogue reproduction of sound. The sound vibration waveforms are recorded as corresponding phys ...

. Unidirectional trams and streetcars operate in many parts of the world, with a significant number running in Continental European cities such as Rotterdam, Amsterdam, Zurich, Berlin, Düsseldorf, and Vienna. In Asia, uni-directional vehicles can be found in Hong Kong (both

and

light rail Light rail (or light rail transit, abbreviated to LRT) is a form of passenger urban rail transit that uses rolling stock derived from tram technology National Conference of the Transportation Research Board while also having some features from ...

) and

Kolkata Kolkata, also known as Calcutta ( its official name until 2001), is the capital and largest city of the Indian state of West Bengal. It lies on the eastern bank of the Hooghly River, west of the border with Bangladesh. It is the primary ...

. In North America, modern uni-directional streetcars operate in

Toronto Toronto ( , locally pronounced or ) is the List of the largest municipalities in Canada by population, most populous city in Canada. It is the capital city of the Provinces and territories of Canada, Canadian province of Ontario. With a p ...

and

Philadelphia Philadelphia ( ), colloquially referred to as Philly, is the List of municipalities in Pennsylvania, most populous city in the U.S. state of Pennsylvania and the List of United States cities by population, sixth-most populous city in the Unit ...

, while historic uni-directional streetcars can be found in

San Francisco San Francisco, officially the City and County of San Francisco, is a commercial, Financial District, San Francisco, financial, and Culture of San Francisco, cultural center of Northern California. With a population of 827,526 residents as of ...

and

El Paso El Paso (; ; or ) is a city in and the county seat of El Paso County, Texas, United States. The 2020 United States census, 2020 population of the city from the United States Census Bureau, U.S. Census Bureau was 678,815, making it the List of ...

. Tram vehicles Rail transport {{rail-transport-stub