HOME

TheInfoList



OR:

A pantograph (or "pan" or "panto") is an apparatus mounted on the roof of an electric
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 ...
or trolley buses to collect power through contact with an
overhead line An overhead line or overhead wire is an electrical cable that is used to transmit electrical energy to electric locomotives, Electric multiple unit, electric multiple units, trolleybuses or trams. The generic term used by the International Union ...
. The term stems from the resemblance of some styles to the mechanical
pantograph A pantograph (, from their original use for copying writing) is a Linkage (mechanical), mechanical linkage connected in a manner based on parallelograms so that the movement of one pen, in tracing an image, produces identical movements in a se ...
s used for copying handwriting and drawings. The pantograph is a common type of current collector; typically, a single or double wire is used, with the return current running through the
rails Rail or rails may refer to: Rail transport *Rail transport and related matters * Railway track or railway lines, the running surface of a railway Arts and media Film * ''Rails'' (film), a 1929 Italian film by Mario Camerini * ''Rail'' (1967 fi ...
. Other types of current collectors include the bow collector and the
trolley pole A trolley pole is a tapered cylindrical pole of wood or metal, used to transfer electricity from a "live" (electrified) overhead line, overhead wire to the control and the electric traction motors of a tram or trolley bus. It is a type of current ...
.


Invention

The pantograph, with a low-friction, replaceable
graphite Graphite () is a Crystallinity, crystalline allotrope (form) of the element carbon. It consists of many stacked Layered materials, layers of graphene, typically in excess of hundreds of layers. Graphite occurs naturally and is the most stable ...
contact strip or "
shoe A shoe is an item of footwear intended to protect and comfort the human foot. Though the human foot can adapt to varied terrains and climate conditions, it is vulnerable, and shoes provide protection. Form was originally tied to function, but ...
" to minimise lateral stress on the contact wire, first appeared in the late 19th century. Early versions include the bow collector, invented in 1889 by Walter Reichel, chief engineer at Siemens & Halske in Germany, and a flat slide-pantograph first used in 1895 by the
Baltimore and Ohio Railroad The Baltimore and Ohio Railroad was the oldest railroads in North America, oldest railroad in the United States and the first steam engine, steam-operated common carrier. Construction of the line began in 1828, and it operated as B&O from 1830 ...
. The familiar diamond-shaped roller pantograph was devised and patented by John Q. Brown of the Key System shops for their
commuter Commuting is periodically recurring travel between a place of residence and place of work or study, where the traveler, referred to as a commuter, leaves the boundary of their home community. By extension, it can sometimes be any regular o ...
trains which ran between
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 the
East Bay The East Bay is the eastern region of the San Francisco Bay Area and includes cities along the eastern shores of San Francisco Bay and San Pablo Bay. The region has grown to include inland communities in Alameda and Contra Costa counties. Wi ...
section of the
San Francisco Bay Area The San Francisco Bay Area, commonly known as the Bay Area, is a List of regions of California, region of California surrounding and including San Francisco Bay, and anchored by the cities of Oakland, San Francisco, and San Jose, California, S ...
in
California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...
. They appear in photographs of the first day of service, 26 October 1903. For many decades thereafter, the same diamond shape was used by electric-rail systems around the world and remains in use by some today. The pantograph was an improvement on the simple
trolley pole A trolley pole is a tapered cylindrical pole of wood or metal, used to transfer electricity from a "live" (electrified) overhead line, overhead wire to the control and the electric traction motors of a tram or trolley bus. It is a type of current ...
, which prevailed up to that time, primarily because the pantograph allows an electric-rail vehicle to travel at much higher speeds without losing contact with the overhead lines, e.g. due to dewirement of the trolley pole. Notwithstanding this, trolley pole current collection was used successfully at up to on the Electroliner vehicles of the
Chicago North Shore and Milwaukee Railroad The Chicago North Shore and Milwaukee Railroad (reporting mark CNSM), also known as the North Shore Line, was an interurban railroad that operated passenger train, passenger and freight train, freight service over an route between the Chicag ...
, also known as the North Shore Line.


Modern use

The most common type of pantograph today is the so-called half-pantograph (sometimes Z-shaped), which evolved to provide a more compact and responsive single-arm design at high speeds as trains got faster. Louis Faiveley invented this type of pantograph in 1955. The half-pantograph can be seen in use on everything from very fast trains (such as the TGV) to low-speed urban tram systems. The design operates with equal efficiency in either direction of motion, as demonstrated by the
Swiss Swiss most commonly refers to: * the adjectival form of Switzerland * Swiss people Swiss may also refer to: Places * Swiss, Missouri * Swiss, North Carolina * Swiss, West Virginia * Swiss, Wisconsin Other uses * Swiss Café, an old café located ...
and Austrian railways whose newest high-performance locomotives, the Re 460 and Taurus, operate with them set in the opposite direction. In Europe the geometry and shape of the pantographs are specified by
CENELEC CENELEC (; ) is responsible for European standardization in the area of electrical engineering. Together with ETSI (telecommunications) and CEN (other technical areas), it forms the European system for technical standardization. Standards harmon ...
, the European Committee for Electrotechnical Standardization. While a pantograph is mainly used to power a railway traction unit, there are certain cases where it has a function other than traction: * Mechanical measurements and tests of new catenary (with or without voltage), on a catenary and contact line inspection car; * General power supply of a measuring car; * Power supply of an air-conditioned train (for example: pantograph mounted on a RENFE van for the 3,000 V DC power supply of the rest of the train via the UIC train line, or heating line), in the absence of a locomotive; * Power supply of a restaurant car when parked on a siding in the absence of a locomotive, under a catenary electrified with 15 kV AC Hz; this system is used on restaurant cars of the Swiss and German railways; * Grounding of the catenary during work carried out from certain work vehicles.


Technical details

The electric transmission system for modern electric rail systems consists of an upper, weight-carrying wire (known as a
catenary In physics and geometry, a catenary ( , ) is the curve that an idealized hanging chain or wire rope, cable assumes under its own weight when supported only at its ends in a uniform gravitational field. The catenary curve has a U-like shape, ...
) from which is suspended a contact wire. The pantograph is spring-loaded and pushes a contact shoe up against the underside of the contact wire to draw the current needed to run the train. The steel rails of the tracks act as the electrical return. As the train moves, the contact shoe slides along the wire and can set up
standing wave In physics, a standing wave, also known as a stationary wave, is a wave that oscillates in time but whose peak amplitude profile does not move in space. The peak amplitude of the wave oscillations at any point in space is constant with respect t ...
s in the wires which break the contact and degrade current collection. This means that on some systems adjacent pantographs are not permitted. Pantographs are the successor technology to
trolley pole A trolley pole is a tapered cylindrical pole of wood or metal, used to transfer electricity from a "live" (electrified) overhead line, overhead wire to the control and the electric traction motors of a tram or trolley bus. It is a type of current ...
s, which were widely used on early streetcar systems. Trolley poles are still used by
trolleybus A trolleybus (also known as trolley bus, trolley coach, trackless trolley, trackless tramin the 1910s and 1920sJoyce, J.; King, J. S.; and Newman, A. G. (1986). ''British Trolleybus Systems'', pp. 9, 12. London: Ian Allan Publishing. .or troll ...
es, whose freedom of movement and need for a two-wire circuit makes pantographs impractical, and some streetcar networks, such as the Toronto streetcar system, which have frequent turns sharp enough to require additional freedom of movement in their current collection to ensure unbroken contact. However, many of these networks, including Toronto's, are undergoing upgrades to accommodate pantograph operation. Pantographs with overhead wires are now the dominant form of current collection for modern electric trains in city street, main and high speed lines because, although more fragile than a
third rail A third rail, also known as a live rail, electric rail or conductor rail, is a method of providing electric power to a railway locomotive or train, through a semi-continuous rigid conductor placed alongside or between the rails of a track (r ...
system, they are safer for public (protection by distance), they may also allow higher voltages (especially AC ones) and higher speed. Pantographs are typically operated by compressed air from the vehicle's braking system, either to raise the unit and hold it against the conductor or, when springs are used to effect the extension, to lower it. As a precaution against loss of pressure in the second case, the arm is held in the down position by a catch. For high-voltage systems, the same air supply is used to "blow out" the
electric arc An electric arc (or arc discharge) is an electrical breakdown of a gas that produces a prolonged electrical discharge. The electric current, current through a normally Electrical conductance, nonconductive medium such as air produces a plasma ( ...
when roof-mounted circuit breakers are used.


Single and double pantographs

Pantographs may have either a single or a double arm. Double-arm pantographs are usually heavier, requiring more power to raise and lower, but may also be more fault-tolerant. On railways of the former
USSR The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...
, the most widely used pantographs are those with a double arm ("made of two rhombs"), but, since the late 1990s, there have been some single-arm pantographs on Russian railways. Some streetcars use double-arm pantographs, among them the Russian KTM-5, KTM-8, LVS-86 and many other Russian-made trams, as well as some Euro-PCC trams in Belgium. American streetcars use either
trolley pole A trolley pole is a tapered cylindrical pole of wood or metal, used to transfer electricity from a "live" (electrified) overhead line, overhead wire to the control and the electric traction motors of a tram or trolley bus. It is a type of current ...
s or single-arm pantographs.


Metro systems and overhead lines

Most
rapid transit Rapid transit or mass rapid transit (MRT) or heavy rail, commonly referred to as metro, is a type of high-capacity public transport that is generally built in urban areas. A grade separation, grade separated rapid transit line below ground su ...
systems are powered by a
third rail A third rail, also known as a live rail, electric rail or conductor rail, is a method of providing electric power to a railway locomotive or train, through a semi-continuous rigid conductor placed alongside or between the rails of a track (r ...
, but some use pantographs, particularly ones that involve extensive above-ground running. Most hybrid metro-tram or 'pre-metro' lines whose routes include tracks on city streets or in other publicly accessible areas, such as (formerly) line 51 of the Amsterdam Metro, the MBTA Green Line, RTA Rapid Transit in Cleveland, Frankfurt am Main U-Bahn, and San Francisco's Muni Metro, use overhead wire, as a standard third rail would obstruct street traffic and present too great a risk of electrocution. Among the various exceptions are several tram systems, such as the ones in
Bordeaux Bordeaux ( ; ; Gascon language, Gascon ; ) is a city on the river Garonne in the Gironde Departments of France, department, southwestern France. A port city, it is the capital of the Nouvelle-Aquitaine region, as well as the Prefectures in F ...
,
Angers Angers (, , ;) is a city in western France, about southwest of Paris. It is the Prefectures of France, prefecture of the Maine-et-Loire department and was the capital of the province of Duchy of Anjou, Anjou until the French Revolution. The i ...
,
Reims Reims ( ; ; also spelled Rheims in English) is the most populous city in the French Departments of France, department of Marne (department), Marne, and the List of communes in France with over 20,000 inhabitants, 12th most populous city in Fran ...
and
Dubai Dubai (Help:IPA/English, /duːˈbaɪ/ Help:Pronunciation respelling key, ''doo-BYE''; Modern Standard Arabic, Modern Standard Arabic: ; Emirati Arabic, Emirati Arabic: , Romanization of Arabic, romanized: Help:IPA/English, /diˈbej/) is the Lis ...
that use a proprietary underground system developed by
Alstom Alstom SA () is a French multinational rolling stock manufacturer which operates worldwide in rail transport markets. It is active in the fields of passenger transportation, signaling, and locomotives, producing high-speed, suburban, regional ...
, called APS, which only applies power to segments of track that are completely covered by the tram. This system was originally designed to be used in the historic centre of Bordeaux because an overhead wire system would cause a visual intrusion. Similar systems that avoid overhead lines have been developed by Bombardier, AnsaldoBreda, CAF, and others. These may consist of physical ground-level infrastructure, or use energy stored in battery packs to travel over short distances without overhead wiring. Overhead pantographs are sometimes used as alternatives to third rails because third rails can ice over in certain winter weather conditions. The MBTA Blue Line uses pantograph power for the entire section of its route that runs on the surface, while switching to third rail power before entering the underground portion of its route. The entire metro systems of
Sydney Sydney is the capital city of the States and territories of Australia, state of New South Wales and the List of cities in Australia by population, most populous city in Australia. Located on Australia's east coast, the metropolis surrounds Syd ...
,
Madrid Madrid ( ; ) is the capital and List of largest cities in Spain, most populous municipality of Spain. It has almost 3.5 million inhabitants and a Madrid metropolitan area, metropolitan area population of approximately 7 million. It i ...
,
Barcelona Barcelona ( ; ; ) is a city on the northeastern coast of Spain. It is the capital and largest city of the autonomous community of Catalonia, as well as the second-most populous municipality of Spain. With a population of 1.6 million within c ...
,
Porto Porto (), also known in English language, English as Oporto, is the List of cities in Portugal, second largest city in Portugal, after Lisbon. It is the capital of the Porto District and one of the Iberian Peninsula's major urban areas. Porto c ...
,
Shanghai Shanghai, Shanghainese: , Standard Chinese pronunciation: is a direct-administered municipality and the most populous urban area in China. The city is located on the Chinese shoreline on the southern estuary of the Yangtze River, with the ...
,
Hong Kong Hong Kong)., Legally Hong Kong, China in international treaties and organizations. is a special administrative region of China. With 7.5 million residents in a territory, Hong Kong is the fourth most densely populated region in the wor ...
,
Seoul Seoul, officially Seoul Special Metropolitan City, is the capital city, capital and largest city of South Korea. The broader Seoul Metropolitan Area, encompassing Seoul, Gyeonggi Province and Incheon, emerged as the world's List of cities b ...
,
Kobe Kobe ( ; , ), officially , is the capital city of Hyōgo Prefecture, Japan. With a population of around 1.5 million, Kobe is Japan's List of Japanese cities by population, seventh-largest city and the third-largest port city after Port of Toky ...
,
Fukuoka is the List of Japanese cities by population, sixth-largest city in Japan and the capital city of Fukuoka Prefecture, Japan. The city is built along the shores of Hakata Bay, and has been a center of international commerce since ancient times. ...
,
Sendai is the capital Cities of Japan, city of Miyagi Prefecture and the largest city in the Tōhoku region. , the city had a population of 1,098,335 in 539,698 households, making it the List of cities in Japan, twelfth most populated city in Japan. ...
,
Jaipur Jaipur (; , ) is the List of state and union territory capitals in India, capital and the List of cities and towns in Rajasthan, largest city of the north-western States and union territories of India, Indian state of Rajasthan. , the city had ...
,
Chennai Chennai, also known as Madras (List of renamed places in India#Tamil Nadu, its official name until 1996), is the capital city, capital and List of cities in Tamil Nadu by population, largest city of Tamil Nadu, the southernmost states and ...
,
Mumbai Mumbai ( ; ), also known as Bombay ( ; its official name until 1995), is the capital city of the Indian state of Maharashtra. Mumbai is the financial capital and the most populous city proper of India with an estimated population of 12 ...
and
Delhi Delhi, officially the National Capital Territory (NCT) of Delhi, is a city and a union territory of India containing New Delhi, the capital of India. Straddling the Yamuna river, but spread chiefly to the west, or beyond its Bank (geography ...
use overhead wiring and pantographs (as well as certain lines of the metro systems in
Beijing Beijing, Chinese postal romanization, previously romanized as Peking, is the capital city of China. With more than 22 million residents, it is the world's List of national capitals by population, most populous national capital city as well as ...
,
Chongqing ChongqingPostal Romanization, Previously romanized as Chungking ();. is a direct-administered municipality in Southwestern China. Chongqing is one of the four direct-administered municipalities under the State Council of the People's Republi ...
,
Noida Noida (), short for New Okhla Industrial Development Authority (ISO: ), is a city located in Gautam Buddha Nagar district of the Indian state of Uttar Pradesh. As per provisional reports of Census of India, the population of Noida in 2011 was ...
,
Hyderabad Hyderabad is the capital and largest city of the Indian state of Telangana. It occupies on the Deccan Plateau along the banks of the Musi River (India), Musi River, in the northern part of Southern India. With an average altitude of , much ...
,
Jakarta Jakarta (; , Betawi language, Betawi: ''Jakartè''), officially the Special Capital Region of Jakarta (; ''DKI Jakarta'') and formerly known as Batavia, Dutch East Indies, Batavia until 1949, is the capital and largest city of Indonesia and ...
,
Tokyo Tokyo, officially the Tokyo Metropolis, is the capital of Japan, capital and List of cities in Japan, most populous city in Japan. With a population of over 14 million in the city proper in 2023, it is List of largest cities, one of the most ...
,
Osaka is a Cities designated by government ordinance of Japan, designated city in the Kansai region of Honshu in Japan. It is the capital of and most populous city in Osaka Prefecture, and the List of cities in Japan, third-most populous city in J ...
,
Nagoya is the largest city in the Chūbu region of Japan. It is the list of cities in Japan, fourth-most populous city in Japan, with a population of 2.3million in 2020, and the principal city of the Chūkyō metropolitan area, which is the List of ...
,
Singapore Singapore, officially the Republic of Singapore, is an island country and city-state in Southeast Asia. The country's territory comprises one main island, 63 satellite islands and islets, and one outlying islet. It is about one degree ...
,
Sapporo is a Cities designated by government ordinance of Japan, designated city in Hokkaido, Japan. Located in the southwest of Hokkaido, it lies within the alluvial fan of the Toyohira River, a tributary of the Ishikari River. Sapporo is the capital ...
,
Budapest Budapest is the Capital city, capital and List of cities and towns of Hungary, most populous city of Hungary. It is the List of cities in the European Union by population within city limits, tenth-largest city in the European Union by popul ...
, and
Mexico City Mexico City is the capital city, capital and List of cities in Mexico, largest city of Mexico, as well as the List of North American cities by population, most populous city in North America. It is one of the most important cultural and finan ...
). Pantographs were also used on the Nord-Sud Company rapid transit lines in Paris until the other operating company of the time,
Compagnie du chemin de fer métropolitain de Paris The Compagnie du chemin de fer métropolitain de Paris S.A. (Paris Metropolitan Railway Company Ltd.), or CMP, was a subsidiary of the Empain group that is the forerunner of the Régie Autonome des Transports Parisiens, RATP, the company managing ...
, bought out the company and replaced all overhead wiring with the standard third rail system used on other lines. Numerous railway lines use both third rail and overhead power collection along different portions of their routes, generally for historical reasons. They include the North London line and West London lines of
London Overground London Overground (also known simply as the Overground) is a Urban rail in the United Kingdom, suburban rail network serving London and its environs. Established in 2007 to take over Silverlink Metro routes, it now serves a large part of Greate ...
, the Northern City Line of Great Northern, three of the five lines in the Rotterdam Metro network, Metro-North Railroad's
New Haven Line The New Haven Line is a commuter rail line operated by the Metro-North Railroad in the U.S. states of New York (state), New York and Connecticut. Running from New Haven, Connecticut, to New York City, the New Haven Line joins the Harlem Line ...
, and the Chicago Transit Authority's Yellow Line. In this last case, the overhead portion was a remnant of the
Chicago North Shore and Milwaukee Railroad The Chicago North Shore and Milwaukee Railroad (reporting mark CNSM), also known as the North Shore Line, was an interurban railroad that operated passenger train, passenger and freight train, freight service over an route between the Chicag ...
's high-speed Skokie Valley Route, and was the only line on the entire Chicago subway system to utilize pantograph collection for any length. As such, the line required railcars that featured pantographs as well as third rail shoes, and since the overhead was a very small portion of the system, only a few cars would be so equipped. The changeover occurred at the grade crossing at East Prairie, the former site of the Crawford-East Prairie station. Here, trains bound for Dempster-Skokie would raise their pantographs, while those bound for Howard would lower theirs, doing so at speed in both instances. In 2005, due to the cost and unique maintenance needs for what only represented a very small portion of the system, the overhead system was removed and replaced with the same third rail power that was used throughout the rest of the system, which allowed all of Chicago's railcars to operate on the line. All the pantographs were removed from the Skokie equipped cars. Until 2010, the Oslo Metro line 1 changed from third rail to overhead line power at Frøen station. Due to the many level crossings, it was deemed difficult to install a third rail on the rest of the older line's single track. After 2010 third rails were used in spite of level crossings. The third rails have gaps, but there are two contact shoes.


Three-phase supply

On some systems using three phase power supply, locomotives and power cars have two pantographs with the third-phase circuit provided by the running rails. In 1901 an experimental high-speed installation, another design from Walter Reichel at Siemens & Halske, used three vertically mounted overhead wires with the collectors mounted on horizontally extending pantographs.


Inclined pantographs

On lines where open wagons are loaded from above, the
overhead line An overhead line or overhead wire is an electrical cable that is used to transmit electrical energy to electric locomotives, Electric multiple unit, electric multiple units, trolleybuses or trams. The generic term used by the International Union ...
may be offset to allow this; the pantographs are then mounted at an angle to the vertical.


Weaknesses

Contact between a pantograph and an overhead line is usually assured through a block of
graphite Graphite () is a Crystallinity, crystalline allotrope (form) of the element carbon. It consists of many stacked Layered materials, layers of graphene, typically in excess of hundreds of layers. Graphite occurs naturally and is the most stable ...
. This material conducts electricity while working as a
lubricant A lubricant (sometimes shortened to lube) is a substance that helps to reduce friction between surfaces in mutual contact, which ultimately reduces the heat generated when the surfaces move. It may also have the function of transmitting forces, ...
. As graphite is brittle, pieces can break off during operation. Poorly-built pantographs can seize the overhead wire and tear it down, and poor-condition wires can damage the pantograph. To prevent this, a pantograph monitoring station can be used. At sustained high speeds, above , friction can cause the contact strip to become red hot, which in turn can cause excessive arcing and eventual failure. In the UK, the pantographs ( Brecknell Willis and Stone Faiveley) of vehicles are raised by air pressure and the graphite contact "carbons" create an air gallery in the pantograph head which release the air if a graphite strip is lost, activating the automatic drop device and lowering the pantograph to prevent damage. Newer electric traction units may use more sophisticated methods which detect the disturbances caused by arcing at the point of contact when the graphite strips are damaged. There are not always two pantographs on an
electric multiple unit An electric multiple unit or EMU is a multiple-unit train consisting of self-propelled carriages using electricity as the motive power. An EMU requires no separate locomotive, as electric traction motors are incorporated within one or a number o ...
but, in cases where there are, the other one can be used if one is damaged; an example of this situation would be a Class 390 ''Pendolino''. The rear pantograph in relation to the direction of travel is often used as to avoid damaging both pantographs in case of entanglements: if the front pantograph was used, debris from an entanglement could cause damage to the rear pantograph, rendering both pantographs and the vehicle inoperable.


Automatic dropping device

Automatic dropping device (ADD) is a device that automatically lowers the pantograph on electric trains to prevent additional damages in case of obstructions or emergencies. It is also known as pantograph dropping device. In Europe, the automatic dropping device is mandatory for trains with operational speeds of 160 km/h or 120 km/h and higher if one or several pantographs are used respectively. Otherwise, the train operators are free to install these device. The damage that causes the pantograph to fall can include the strip head, the pantograph head and other parts. The ADD mostly uses a pneumatic system to detect a damage. For example, a broken contact strip will cause a pressure drop in the air tube inside. On non-pneumatic pantographs (mostly tramway or metro), solutions as a pin on the pantograph head can pull a cable which lower pantograph. Nevertheless, infrastructure are free to impose it and performances (distance, force, time...) are not defined Time reaction and reaction to quit overhead contact line are defined for main line use. This function can be different to wearing detection made of a tube or insert place higher than ADD tube.


Other

Several pantograph head profiles exist to meet electrical and mechanical infrastructure gauges of each country. In Europe, two interoperable profiles were defined with 1600 and 1950 mm length. An infrastructure can accept several head profiles, especially with conductive or insulated horns. The Variopanto is a head with two possible lengths. Flat pantographs are emerging to fit on narrow roof gauges, allowing flat roofs and reduced aerodynamic impact. They are made of an insulated lower arm contrary to a "classic" pantograph fixed on insulators. Example: ETR1000 pantograph


See also

* Bow collector * Current collector * Pantographs and underbody collectors *
Railway electrification system Railway electrification is the use of electric power for the propulsion of rail transport. Electric railways use either electric locomotives (hauling passengers or freight in separate cars), electric multiple units ( passenger cars with their own ...
*
Trolley pole A trolley pole is a tapered cylindrical pole of wood or metal, used to transfer electricity from a "live" (electrified) overhead line, overhead wire to the control and the electric traction motors of a tram or trolley bus. It is a type of current ...


References

{{Authority control Locomotive parts Tram technology Electric buses de:Stromabnehmer#Scherenstromabnehmer