An early development of an experimental tramway in Toronto, Ontario, was built in 1883, having been developed by John Joseph Wright, brother of swindler Whitaker Wright. While Wright may have assisted in the installation of electric railways at the Canadian National Exhibition (CNE), and may even have used a pole system, there is no evidence about this. Likewise, Wright never filed or was issued a patent.[3]
Credit for development of the first working trolley pole is given to Charles Joseph Van Depoele, a Belgian engineer who moved to the United States in 1869. Van Depoele made the first public demonstration of the spring-loaded device on a temporary streetcar line installed at the Toronto Industrial Exhibition (now the CNE) in autumn 1885.[2] Depoele's first trolley pole was "crude" and not very reliable, and he reverted to using the troller system of current collection for a commercial installation on a streetcar system in South Bend, Indiana, which opened on November 14, 1885, and on one in Montgomery, Alabama, in April 1886. However, within a few months, Van Depoele switched to the trolley-pole system for the Montgomery operation.[2] Van Depoele and fellow inventor Frank J. Sprague were "working on similar ideas at about the same time",[4] and Sprague employed trolley-pole current collection on an electric streetcar system he installed in Richmond, Virginia, in 1888, also improving the trolley pole wheel and pole designs. Known as the Richmond Union Passenger Railway, this 12-mile (19km) system was the first large-scale trolley line in the world, opening to great fanfare on February 12, 1888.[5]
The grooved trolley wheel was used on many large city systems through the 1940s and 1950s; it was generally used on systems with "old" style round cross sectional overhead wire. The trolley wheel was problematic at best; the circumferential contact of the grooved wheel bearing on the underside of the overhead wire provided minimal electrical contact and tended to arc excessively, increasing overhead wire wear. The newer sliding carbontrolley shoe was generally used with a newer grooved overhead trolley wire of a roughly "figure 8" cross section. The sliding trolley shoe provided better electrical contact (with a reduction in arcing), and it dramatically reduced overhead wire wear. Many systems began converting to the sliding trolley shoe in the 1920s; Milwaukee, Wisconsin converted its large system in the late 1920s. Philadelphia did not convert its trolley wheels on its remaining streetcars until 1978.[citation needed] Although a streetcar with a trolley wheel may evoke an antique look, the trolley shoe is modern and more practical as well as economical.
Description of the device
A trolley pole is not attached to the overhead wire. The pole sits atop a sprung base on the roof of the vehicle, with springs providing the pressure to keep the trolley wheel or shoe in contact with the wire. If the pole is made of wood, a cable brings the electric current down to the vehicle. A metal pole may use such a cable, or may itself be electrically "live", requiring the base to be insulated from the vehicle body.
Modern trolley poles as installed on Vancouver's low-floor trolley buses
On systems with double-ended tram cars capable of running in both directions, the trolley pole must always be pulled behind the car and not pushed, or "dewiring" is very likely, which can cause damage to the overhead wires. At terminus points, the conductor must turn the trolley pole around to face the correct direction, pulling it off the wire either with a rope or a pole and walking it around to the other end. In some cases, two trolley poles are provided, one for each direction: in this case it is a matter of raising one and lowering the other. Since the operator could raise the pole at one end whilst the conductor lowered the other, this saved time and was much easier for the conductor. Care had to be taken to raise the downed pole first, to eliminate the damage caused by arcing between the pole and wire. In the US, the dual-pole system was the most common arrangement on double-ended vehicles. However, pushing of the pole (called "back-poling" in the US or "spear-poling" in Australia), was quite common where the trams were moving at slow speeds, such as at wye terminals (also known as reversers) and whilst backing into the sheds.
Trolley retrievers on the back of a 1949 trolleybus
Trolley poles are usually raised and lowered manually by a rope from the back of the vehicle. The rope feeds into a spring reel mechanism, called a "trolley catcher" or "trolley retriever". The trolley catcher contains a detent, like that in an automotive shoulder safety belt, which "catches" the rope to prevent the trolley pole from flying upward if the pole is dewired. The similar looking retriever (see photo) adds a spring mechanism that yanks the pole downward if it should leave the wire, pulling it away from all overhead wire fittings. Catchers are commonly used on trams operating at lower speeds, as in a city, whilst retrievers are used on suburban and interurban lines to limit damage to the overhead at speed.
On some older systems, the poles were raised and lowered using a long pole with a metal hook. Where available, these may have been made of bamboo due to its length, natural straightness and strength, combined with its relative light weight and the fact that it is an insulator. Trolleybuses usually carried one with the vehicle, for use in the event of dewirement, but tram systems usually had them placed along the route at locations where the trolley pole would need reversing.
The poles used on trolleybuses are typically longer than those used on trams, to allow the bus to take fuller advantage of its not being restricted to a fixed path in the street (the rails), by giving a degree of lateral steerability, enabling the trolleybus to board passengers at curbside.
Single- and double-pole usage
When used on a tram or trolley car (i.e. a railway vehicle), a single trolley pole usually collects current from the overhead wire, and the steel rails on the tracks act as the electrical return. To reduce electrolytic corrosion of underground pipes and metallic structures, most tram lines are operated with the wire positive with respect to the rails. Trolleybuses, on the other hand, must use two trolley poles and dual overhead wires, one pole and wire for the positive "live" current, the other for the negative or neutral return. The tramway system in Havana, Cuba, also utilized the dual-wire system,[6] as did the Cincinnati, Ohio streetcar system.
Decline in usage on railways
Pantograph(left) and trolley pole in use on Queens Quay West, Toronto
All trolleybuses use trolley poles, and thus trolley poles remain in use worldwide, wherever trolleybuses are in operation (some 315 cities as of 2011[update]),[7] and several manufacturers continue to make them, including Kiepe, Škoda and Lekov.
However, on most railway vehicles using overhead wire, the trolley pole has given way to the bow collector or, later, the pantograph, a folding metal device that presses a wide contact pan against the overhead wire. While more complex than the trolley pole, the pantograph has the advantage of being almost free from dewiring, being more stable at high speed, and being easier to raise and lower automatically. Also, on double-ended trams, they eliminate the need to manually turn the trolley pole when changing direction (although this disadvantage can be overcome to some extent through the use of trolley reversers). The use of pantographs (or bow collectors) exclusively also eliminates the need for wire frogs (switches in the overhead wiring) to make sure the pole goes in the correct direction at junctions.
The trolley pole with a shoe at its tip is problematic for longer modern streetcars that draw more electricity than older streetcars. In Toronto, the trolley pole shoe contains a carbon insert to provide electrical contact with the overhead wire and to lower the shoe to clear overhead wire hangers. Carbon inserts wear out and must be periodically replaced. The trolley shoe inserts on Toronto's modern Flexity Outlook streetcars quickly wear out in rainy conditions, lasting as little as eight hours instead of the expected one to two days for shorter older streetcars. The extra current draw shortens the life of the carbon insert. A worn-out carbon insert would damage the overhead wire, stopping streetcar service.[8]
Overhead over a switch in Toronto: Two runners for pantographs flank the trolley pole frog.
Trams or light rail cars equipped with pantographs normally cannot operate on lines with overhead wiring designed for trolley-pole collection. For this reason, these systems and a few others worldwide retain use of trolley poles, even on new streetcars, in order to avoid the difficulty and expense of modifying long stretches of existing overhead wires to accept pantographs.
However, the Toronto Transit Commission, with the impending replacement of its legacy CLRV and ALRV with new Flexity Outlook cars, is converting its overhead power supply to be compatible with both trolley poles and pantographs on an interim basis, as the CLRVs and ALRVs use only trolley poles while the Flexity fleet is equipped for both trolley poles and pantographs. Starting September 12, 2017, streetcars on route 509 Harbourfront started to use pantographs while those on route 510 Spadina continued to use trolley poles along the same section of track on Queens Quay West.[9] (On May 14, 2018, 510 Spadina switched to pantographs.[10])
Upon their introduction, trolley poles and the new electrical technology they represented were fascinating to writers, with their lightning-like sparks and power.
In January 1889, Boston introduced its first electric streetcars, which became so popular and noteworthy that poet Oliver Wendell Holmes composed a verse about the new trolley pole technology, and the sparking contact shoe at its apex:[11]
Since then on many a car you'll see A broomstick as plain as plain can be; On every stick there's a witch astride— The string you see to her leg is tied.
In 1947, composer Samuel Barber wrote the now-classic orchestral and vocal piece Knoxville: Summer of 1915, based on the childhood reminiscences of James Agee. Partway through the composition, the singer refers to a noisy passing streetcar, with its overhead trolley pole and sparks:[12]
A streetcar raising into iron moan; stopping; belling and starting, stertorous; rousing and raising again its iron increasing moan and swimming its gold windows and straw seats on past and past and past, the bleak spark crackling and cursing above it like a small malignant spirit set to dog its tracks;
A tram is a type of urban rail transit consisting of a rail vehicle, either individual railcars or self-propelled trains coupled by a multiple unit, that runs on tramway tracks on urban public streets; some include segments on segregated right-of-way. The tramlines or networks operated as public transport are called tramways or simply trams/streetcars. Many recently built tramways use the contemporary term light rail.
Trolley may refer to:
A trolleybus is an electric bus that draws power from dual overhead wires using spring-loaded trolley poles. Two wires, and two trolley poles, are required to complete the electrical circuit. This differs from a tram or streetcar, which normally uses the track as the return path, needing only one wire and one pole. They are also distinct from other kinds of electric buses, which usually rely on batteries. Power is most commonly supplied as 600-volt direct current, but there are exceptions.
An overhead line or overhead wire is an electrical cable that is used to transmit electrical energy to electric locomotives, electric multiple units, trolleybuses or trams. The generic term used by the International Union of Railways for the technology is overhead line. It is known variously as overhead catenary, overhead contact line (OCL), overhead contact system (OCS), overhead equipment (OHE), overhead line equipment, overhead lines (OHL), overhead wiring (OHW), traction wire, and trolley wire.
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 railway track. It is used typically in a mass transit or rapid transit system, which has alignments in its own corridors, fully or almost fully segregated from the outside environment. Third-rail systems are usually supplied from direct current electricity.
Charles Joseph Van Depoele was a Belgian-American electrical engineer, inventor, and pioneer in electric railway technology, including the first trolley pole.
Ground-level power supply, also known as surface current collection or, in French, alimentation par le sol, is a concept and group of technologies whereby electric vehicles collect electric power at ground level from individually-powered segments instead of the more common overhead lines. Ground-level power supply was developed for aesthetic reasons, to avoid the presence of overhead lines in city centres.
A pantograph is an apparatus mounted on the roof of an electric train, tram or electric bus to collect power through contact with an overhead line. The term stems from the resemblance of some styles to the mechanical pantographs used for copying handwriting and drawings.
Conduit current collection is an obsolete system that was used by some electric tramways to pass current to streetcars via a "conduit", a small tunnel under the roadway. Modern systems fall under the term ground-level power supply.
The Toronto streetcar system is a network of eleven streetcar routes in Toronto, Ontario, Canada, operated by the Toronto Transit Commission (TTC). It is the third busiest light-rail system in North America. The network is concentrated primarily in Downtown Toronto and in proximity to the city's waterfront. Much of the streetcar route network dates from the 19th century. Three streetcar routes operate in their own right-of-way, one in a partial right-of-way, and six operate on street trackage shared with vehicular traffic with streetcars stopping on demand at frequent stops like buses. Since 2019, the network has used low-floor streetcars, making it fully accessible.
A bow collector is one of the three main devices used on tramcars to transfer electric current from the wires above to the tram below. While once very common in continental Europe, it was replaced by the pantograph or the trolley pole, itself often later replaced by the pantograph.
Guided Light Transit was the name of guided bus technology and associated infrastructure designed and manufactured by Bombardier Transportation. It was installed in two French cities: Nancy and Caen. The Caen system was closed in 2017 and replaced by conventional trams, while the Nancy system was closed in March 2023 and is to be replaced by trolleybuses.
The Saint-Étienne tramway is a tram system in the city of Saint-Étienne in the Rhône-Alpes (France) that has functioned continuously since its opening in 1881. The first tramway line was steam-operated and was opened by the Chemins de Fer à Voie étroite de Saint-Étienne (CFVE) on 4 December 1881, stretching for 5.5 km between La Terrasse and Bellevue. The CFVE took over the Compagnie des Tramways Électriques de Saint-Étienne lines and discontinued the use of steam in 1912.
A trolleytruck is a trolleybus-like vehicle used for carrying cargo instead of passengers. A trolleytruck is usually a type of electric truck powered by two overhead wires, from which it draws electricity using two trolley poles. Two current collectors are required in order to supply and return current, because the return current cannot pass to the ground since trolleytrucks use tires that are insulators. Lower powered trucks, such as might be seen on the streets of a city, tend to use trolley poles for current collection. Higher powered trucks, such as those used for large construction or mining projects, may exceed the power capacity of trolley poles and have to use pantographs instead. Trolleytrucks have been used in various places around the world and are still in use in cities in Russia and Ukraine, as well as at mines in North America and Africa. Because they draw power from the mains, trolleytrucks can use renewable energy sources – modern trolleytrucks systems are under test in Sweden and Germany along highways using diesel–electric hybrids to reduce emissions.
The stud contact system is an obsolete ground-level power supply system for electric trams. Power supply studs were set in the road at intervals and connected to a buried electric cable by switches operated by magnets on the tramcars. Current was collected from the studs by a "skate" or "ski collector" under the tramcar. The system was popular for a while in the early 1900s but soon fell out of favour because of the unreliability of the magnetic switches, largely due to friction and rapid corrosion affecting its cast iron moving components.
A current collector is a device used in trolleybuses, trams, electric locomotives and EMUs to carry electric power (current) from overhead lines, electric third rails, or ground-level power supplies to the electrical equipment of the vehicles. Those for overhead wires are roof-mounted devices, those for rails are mounted on the bogies.
A rubber-tyred tram is a development of the guided bus in which a vehicle is guided by a fixed rail in the road surface and draws current from overhead electric wires.
The Flexity Outlook is the latest model of streetcar in the rolling stock of the Toronto streetcar system owned by the Toronto Transit Commission (TTC). Based on the Bombardier Flexity, they were first ordered in 2009 and were built by Bombardier Transportation in Thunder Bay and Kingston, Ontario, with specific modifications for Toronto, such as unidirectional operation and the ability to operate on the unique broad Toronto gauge.
Stalybridge, Hyde, Mossley & Dukinfield Tramways & Electricity Board (SHMD) was a public transport and electricity supply organisation formed by Act of the British Parliament in August 1901. It was a joint venture between the borough councils of Stalybridge, Hyde, Mossley and Dukinfield. The system was officially opened on 21 May 1904.
The Cantono Frigerio system was an Italian electric power supply for trackless trolleybuses with two wires about 20 inches (50 cm) apart being contacted by a four-wheeled collector on a single trolley pole. In English publications it was often described as Filovia system although the Italian term filovia means literally wire way, i.e. a trolleybus line or a trolleybus system.
↑ Morrison, Allen (1996). Latin America by Streetcar: A Pictorial Survey of Urban Rail Transport South of the U.S.A., p. 55. New York: Bonde Press. ISBN0-9622348-3-4.
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