Ground-level power supply

Last updated
Bordeaux tramway with ground-level power supply Bordeaux-tram-aps-near-Roustaing.jpg
Bordeaux tramway with ground-level power supply

Ground-level power supply, also known as surface current collection or, in French, alimentation par le sol ("feeding via the ground"), 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.

Contents

Ground-level power supply systems date to the beginning of electric tramways, with some of the earliest such systems using conduit current collection. Since the turn of the 21st century, systems such as the Alstom APS, Ansaldo Tramwave, CAF ACR, and Elways have been introduced that use modern technology to eliminate some limits and dangers of the older systems, and to supply power for buses, trucks, and electric cars. With the increased efficiency and energy density of capacitor- and battery-powered systems, ground-level power supply systems are used in smaller portions of the line to charge batteries—for example, during station stops for buses and trains.

Early systems

Conduit for current collection between the rails of streetcars in Washington, D.C., 1939. First installed in 1895, it remained in operation until 1962 Washington, D.C. Aerial view of a street corner2.jpg
Conduit for current collection between the rails of streetcars in Washington, D.C., 1939. First installed in 1895, it remained in operation until 1962
Remaining conduit tram track on the ramp to the abandoned Kingsway tram subway in London, with plants growing in the conduit Kingsway tramway subway (6266160469).jpg
Remaining conduit tram track on the ramp to the abandoned Kingsway tram subway in London, with plants growing in the conduit

Conduit current collection systems were implemented as early as 1881 with the Gross-Lichterfelde Tramway. [3] : Appendix I  The system is primarily composed of a channel, or conduit, excavated under the roadway; the conduit is positioned either between the running rails, much in the same fashion as the cable for cable cars, [4] or underneath one of the rails; a car is connected to a "plow" that runs through the conduit and delivers power from two electric rails at the sides of the conduit to the car's electric motor. [5] Plows were manually attached and detached from cars as they switched rail lines. [4]

Cleveland opened a conduit line in 1885. [1] Tram companies in Budapest trialed a conduit current collector system in 1887. Overhead lines were met with public opposition for aesthetic reasons, so the contractor Siemens-Halske implemented a concrete conduit underneath one of the trolley rails, with a narrow opening that allowed a "plow" to be inserted and make electrical contact with wires held by insulators at either side of the conduit. The system was used in several cities in Europe and the United States, where it was known as the "Budapest System". [5] [6] Washington, D.C. installed its first conduit current collection system in 1895. By 1899 all downtown lines were converted to the conduit system, which remained in operation until 1962. [1] The system was generally safe, but tended to get clogged by mud and dirt. The system fell out of favor within a few years due to the cost of excavating the conduit, and was generally replaced with overhead lines. [5]

Stud contact systems were implemented from 1899 to 1921. Systems by the inventors Dolter and Diatto were used in Tours, Paris, and several towns in England. Power was supplied from studs set in the road at intervals, which connected to the traveling cars with contact shoes or contact skis. The studs were cylinders with their tops flush with the road surface. Underneath there was a switch mechanism that made an electrical connection with the top of the stud when a car with a strong electromagnet at its underside passed over it. The Diatto switches contained mercury, which often leaked or adhered to the side of the cylinder and kept the exposed top electrified. The Dolter switches used pivot arms, which tended to get stuck in the electrified position. Similar systems were operated by Thomson-Houston in Monaco from 1898 to 1903, and by František Křižík in Prague on the King Charles Bridge from 1903 to 1908. [3] : 109–116  Stud contact systems were short-lived due to safety issues. [7]

Conduit current collection systems were used in several major cities, including Monaco, Dresden, Prague, Tours, Washington, and London, [3] : 44  but posed maintenance issues and road safety issues. The Bordeaux and Washington conduit systems remained the last in operation until being decommissioned in 1958 [7] and 1962, [2] respectively. For decades, these systems were not reintroduced because they didn't meet modern safety standards. [7]

Modern systems

A number of ground-level power supply systems were developed from the 1970s through the 1990s, [8] but were not reliable or safe enough for commercial use. [9]

The first ground-level power supply system developed to modern safety standards was the Ansaldo Stream, [7] although a competing system, Alstom APS, was the first to be commercially implemented in 2003. This success led to a proliferation of commercial implementations of ground-level power supply systems. [10]

During the late 2010s, advancements in technology led to ground-level power supplies seeing increasing reliability and economic feasibility. [11]

Electric road systems

Sweden

Electric truck driving on a public road with Elways-Evias ground-level power supply, near Arlanda airport, 2019. Elways electric truck dynamic charging electric road eRoadArlanda project 2019-05-16.jpg
Electric truck driving on a public road with Elways-Evias ground-level power supply, near Arlanda airport, 2019.

Electric roads power and charge electric vehicles while driving. Sweden has tested electric road systems that charge the batteries of trucks and electric cars, and among the tested systems are two ground-level power supply systems tested since 2017, in-road rail by Elways-Evias and on-road rail by Elonroad. [12] Elonroad later developed an in-road rail system for highway use at speeds up to 130 kilometres per hour (81 mph). [13] The systems were found to be more economical than the tested overhead line system and dynamic inductive charging system. The in-road rail system is planned to deliver up to 800 kW per vehicle traveling over a powered segment of the rail, and the system is estimated to be the most cost-effective among the four tested systems. The new systems are expected to be safe, with segments of the rail being powered only when a vehicle is traveling over them. [14] The rails have been tested while submerged in salt water and were found to be safe for pedestrians. [15]

France

The co-director for one of the French Ministry of Ecology working groups on electric road systems stated that rail-based ERS are the most advantageous, though the specific rail technology has yet to be standardized. France plans to invest 30 to 40 billion euro by 2035 in an electric road system spanning 8,800 kilometers. Ground-level power supply technologies are considered the most likely candidates for electric roads. [16] Two projects for assessment of electric road technologies have been announced in 2023. The first French public road with an electric road system is planned to open in 2024 using a ground-level power supply system derived from Alstom APS. [17] The second, with technology developed by Elonroad, is scheduled to undergo laboratory testing for skid effects on motorcycles before being deployed along two kilometers on the A10 autoroute south of Paris. [13]

Standardization

Alstom, Elonroad, and other companies have, in 2020, begun drafting a standard for ground-level power supply electric roads. [18] [19] The European Commission published in 2021 a request for regulation and standardization of electric road systems. [20] Shortly afterward, a working group of the French Ministry of Ecology recommended adopting a European electric road standard formulated with Sweden, Germany, Italy, the Netherlands, Spain, Poland, and others. [21]

The first standard for electrical equipment on board a vehicle powered by a rail electric road system (ERS) has been published in late 2022. [22] The standard, CENELEC Technical Standard 50717, specifies the following: an ERS voltage of 750 volts; a contact shoe capable of withstanding impact of gravel and similar road debris at the maximum operating speed; a weak link that breaks off the current collector at the structural fixing points if the force is larger than the maximum specified by the vehicle manufacturer; automatic monitoring of the presence of ERS infrastructure; automatic engagement and disengagement; a presence signal that may be analog or digital, and optional standard bidirectional communication; ease of inspection and replacement for the wearing parts of the sliding contact; and standard tests, markings, maintenance, and operational environment conditions. [23] The 50717 standard does not encompass, but specifies for normative purposes, three architectures for ERS infrastructure: Type A architecture with two parallel surface-level conductive rails, one positive and one negative; Type B architecture with a single surface-level or raised track with short segments where each two segments in series consist of one positive and one negative segment; and Type C architecture with three parallel conductive rails, one positive and one negative below surface level in 1.5 cm wide channels, and one or more rails earthed at surface level. [23]

Following standards, encompassing "full interoperability" and a "unified and interoperable solution" for ground-level power supply, are scheduled to be published by the end 2024, detailing complete "specifications for communication and power supply through conductive rails embedded in the road". [24] [25]

Modern implementations

Ansaldo Stream

The first modern ground-level power supply system to be developed is the Ansaldo Stream system. STREAM is an acronym that stands for "Sistema di TRasporto Elettrico ad Attrazione Magnetica", meaning "System of Electric Transport by Magnetic Attraction". The system uses a channel in the road made of insulating composite fiberglass material which contains a flexible copper strip; a vehicle passing over the channel with a special magnetic contact shoe raises the conductor to the surface, allowing power to flow to the vehicle. Segments of the strip are powered only when a vehicle passes over them. The system was developed in 1994 [26] and trialed on a public tram line in 1998, [7] which was eventually dismantled in 2012. [27]

Alstom APS

A section of APS track showing the neutral sections at the end of the powered segments plus one of the insulating joint boxes which mechanically and electrically join the APS rail segments (Bordeaux) Bordeaux-aps+isolation&joint.jpg
A section of APS track showing the neutral sections at the end of the powered segments plus one of the insulating joint boxes which mechanically and electrically join the APS rail segments (Bordeaux)

Alstom APS uses a third rail placed between the running rails, divided electrically into 11-metre segments. These segments automatically switch on or off by radio control according to whether a tram is passing over them, thereby eradicating any risk to other road users. The tram has two collector shoes, and two segments of rail are active at any given time, to avoid interruption of power when passing between segments. APS was developed by Innorail, a subsidiary of Spie Enertrans but was sold to Alstom when Spie was acquired by Amec. It was originally created for the Bordeaux tramway, which was constructed from 2000 and opened in 2003, becoming the first modern commercial ground-level power supply system. From 2011, the technology has been used in a number of other cities around the world. [28] [29]

The French government reports no electrocutions or electrification accidents on any tramway in France from as early as 2003 [30] until as recently as December 31, 2020. [30] [31]

Alstom further developed the APS system for use with buses and other vehicles. [32] The system has been tested for compatibility with snow plows and for safety under exposure to snow, ice, salting, and saturated brine. [33] Alstom will trial its electric road system on a public road in the Rhône-Alpes region between 2024 and 2027. [17]

CAF ACR

CAF ACR-equipped Urbos 3 tram running through central Seville, 2015. The tram is powered by supercapacitors charged by a ground-level power supply. Seville Metro Train.JPG
CAF ACR-equipped Urbos 3 tram running through central Seville, 2015. The tram is powered by supercapacitors charged by a ground-level power supply.

Construcciones y Auxiliar de Ferrocarriles (CAF) trialed its Acumulador de Carga Rápida (ACR) ground-level power supply system in 2007 in Seville. Sections of the Seville MetroCentro tramway around the Seville Cathedral were converted to the ACR ground-level power supply system. ACR's first commercial installation was aboard Urbos trams supplied to MetroCentro in 2011, allowing the permanent removal of overhead lines around the cathedral. [34]

Line 1 of the Tranvía de Zaragoza has also used ACR since its second construction phase was completed in 2013. The use of ACR avoided the installation of overhead lines in the city's historic centre. [35] [36]

ACR was included in the Newcastle Light Rail in Australia and Luxembourg's new tram system. [37] [38]

Ansaldo Tramwave

Derived from Ansaldo Stream and developed by Italian company Ansaldo STS (which later became Hitachi Rail STS), the Ansaldo TramWave ground-level power supply system successfully entered commercial application in 2017, with the opening of Zhuhai tram Line 1 first phase in China. The tram is the first fully low-floor tram system adopting ground level power supply technology. [39] Later in 2017, Western Suburb Line in Beijing was opened with the same technology from Ansaldo. [40] The technology has been licensed to CRRC Dalian and all the technologies were transferred to China. [41]

Related Research Articles

<span class="mw-page-title-main">Transport in France</span> Overview of the transport in France

Transportation in France relies on one of the densest networks in the world with 146 km of road and 6.2 km of rail lines per 100 km2. It is built as a web with Paris at its center. Rail, road, air and water are all widely developed forms of transportation in France.

<span class="mw-page-title-main">Tram</span> Street-running light railcar

A tram is a type of urban rail transit. It consists of a rail vehicle, either alone or coupled in a multiple train unit, traveling on tramway tracks on public urban 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.

<span class="mw-page-title-main">Overhead line</span> Cable that provides power to electric railways, trams, and trolleybuses

An overhead line or overhead wire is an electrical cable that is used to transmit electrical energy to electric locomotives, 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.

<span class="mw-page-title-main">Third rail</span> Method of providing electric power to a railway train

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.

<span class="mw-page-title-main">Alstom Citadis</span> Family of low-floor trams and light rail vehicles

The Alstom Citadis is a family of low-floor trams and light rail vehicles built by Alstom. As of 2017, over 2,300 Citadis trams have been sold and 1,800 tramways are in revenue service throughout the world, with operations in all six inhabited continents. An evolution of Alstom's earlier TFS vehicle, most Citadis vehicles are made in Alstom's factories in La Rochelle, Reichshoffen and Valenciennes, France, and in Barcelona, Spain, and Annaba, Algeria.

<span class="mw-page-title-main">Pantograph (transport)</span> Power collection apparatus used by trains and light rail

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.

<span class="mw-page-title-main">Conduit current collection</span>

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.

<span class="mw-page-title-main">Tramway track</span> Type of railway track used for trams or light rail transit

Tramway track is used on tramways or light rail operations. Grooved rails are often used to provide a protective flangeway in the trackwork in city streets. Like standard rail tracks, tram tracks consist of two parallel steel rails.

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.

<span class="mw-page-title-main">Reims tramway</span> French tram system

Reims tramway is a tram system in the French city of Reims, which opened in April 2011. It travels north to south, through the city, along 11.2 kilometres (7.0 mi) of route.

<span class="mw-page-title-main">Current collector</span> Device that carries electrical power from lines or rails

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.

<span class="mw-page-title-main">Rubber-tyred tram</span> Development of the guided bus

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.

<span class="mw-page-title-main">Trams in France</span>

Trams in France date from 1837 when a 15 km steam tram line connected Montrond-les-Bains and Montbrison in the Loire. With the development of electric trams at the end of the 19th century, networks proliferated in French cities over a period of 15 years. Although nearly all of the country's tram systems were replaced by bus services in the 1930s or shortly after the Second World War, France is now in the forefront of the revival of tramways and light rail systems around the globe. Only tram lines in Lille and Saint-Étienne have operated continuously since the 19th century; the Marseille tramway system ran continuously until 2004 and only closed then for 3 years for extensive refurbishment into a modern tram network. Since the opening of the Nantes tramway in 1985, more than twenty towns and cities across France have built new tram lines. As of 2020, there are 29 operational tram networks in France, with 3 more planned. France is also home to Alstom, a leading tram manufacturer.

<span class="mw-page-title-main">Conductive charging</span>

Conductive charging is conductive power transfer that replaces the conductive wires between the charger and the charged device with conductive contacts. Charging infrastructure in the form of a board or rail delivers the power to a charging device equipped with an appropriate receiver, or pickup. When the infrastructure recognizes a valid receiver it powers on, and power is transferred.

<span class="mw-page-title-main">Rio de Janeiro Light Rail</span> Light rail system in Brazil

Rio de Janeiro Light Rail is a modern light rail system serving Rio de Janeiro, Brazil. The system is among several new public transport developments in the region ahead of the city's successful bid for the 2016 Summer Olympics. Its official name is VLT Carioca, the initialism "VLT" being equivalent to the English term light rail.

<span class="mw-page-title-main">Electric road</span> Road which supplies electric power to vehicles travelling on it

An electric road, eroad, or electric road system (ERS) is a road which supplies electric power to vehicles travelling on it. Common implementations are overhead power lines above the road and ground-level power supply through conductive rails or inductive coils embedded in the road. Overhead power lines are limited to commercial vehicles while ground-level power can be used by any vehicle, which allows for public charging through power metering and billing systems. Of the three systems, ground-level conductive rails are estimated to be the most cost-effective. Korea was the first to implement an induction-based public electric road with a commercial bus line in 2013 after testing an experimental shuttle service in 2009. Sweden has been performing assessments of various electric road technologies since 2013 and expects to start formulating a national electric road system in 2022 and finish planning by 2033.

<span class="mw-page-title-main">Acumulador de Carga Rápida</span> Battery electric tram system from Spain

Acumulador de Carga Rápida (ACR) is a battery electric tram system marketed by Construcciones y Auxiliar de Ferrocarriles (CAF) of Spain. Trams equipped with ACR are fast-charged while at stops; elsewhere they require no overhead line, which is desirable for reasons of safety, reliability, cost, and aesthetics. It also allows regenerative braking where direct current electrification systems cannot return (much) energy to the grid.

<span class="mw-page-title-main">Alstom APS</span> Alternative method of third rail electrical pick-up for street trams

Alstom APS, also known as Alimentation par Sol or Alimentation Par le Sol, is a form of ground-level power supply for street trams and, potentially, other vehicles. APS was developed by Innorail, a subsidiary of Spie Enertrans, but was sold to Alstom when Spie was acquired by Amec. It was originally created for the Bordeaux tramway, which was constructed from 2000 and opened in 2003. From 2011, the technology has been used in a number of other cities around the world.

The Swedish Transport Administration electric road program or Swedish Transport Administration Electrification Program is a program involving the assessment, planning, and implementation of an electric road national infrastructure for Sweden by Trafikverket, the Swedish Transport Administration.

References

  1. 1 2 3 John H. White, Jr., "Public Transport in Washington before the Great Consolidation of 1902", Records of the Columbia Historical Society, Washington, D.C., 66/68 (46): 216–230
  2. 1 2 Jack W. Boorse (January 2005), "Directly and Indirectly Reducing Visual Impact of Electric Railway Overhead Contact Systems", Transportation Research Record, 1930 (1), doi:10.1177/0361198105193000107
  3. 1 2 3 Gerry Colley (November 27, 2014), Electrifying the streets: the surface-contact controversy in give English towns 1880-1920 (PDF), doi:10.21954/ou.ro.0000d65c
  4. 1 2 Dewi Williams (2004), London Trams: current collectors (ploughs)
  5. 1 2 3 Eric Schatzberg (2001), Culture and Technology in the City: Opposition to Mechanized Street Transportation in Late-Nineteenth-Century America, MIT Press
  6. ↑ Legát, Tibor; Zsolt L. Nagy; Gábor Zsigmond (2010). "Bevezető [Introduction]". Számos villamos [Numbered tram] (in Hungarian). Budapest: Jószöveg. pp. 6–12. ISBN   978-615-5009-15-0.
  7. 1 2 3 4 5 J Baggs (March 9, 2006), "5.1 Ground Level Power Supply", Wire-Free Traction System Technology Review (PDF), Edinburgh Tram Network
  8. ↑ John D Swanson (2003), "Ground level switched contact systems", Light Rail Without Wires - A Dream Come True? (PDF), Transportation Research Board
  9. ↑ Michael P. Hennessey (January 1994), Evaluation of the E-TRAN Vehicle Propulsion Concept (PDF), Minnesota Department of Transportation, pp. 11–12
  10. ↑ John D. Swanson (April 7, 2019), "Continued Advances in Light Rail / Streetcar Vehicle Off-Wire Technology" (PDF), Transportation Research Board
  11. ↑ Guerrieri, M. (2019), "Catenary-Free Tramway Systems: Functional and Cost–Benefit Analysis for a Metropolitan Area.", Urban Rail Transit (5): 289–309, doi: 10.1007/s40864-019-00118-y
  12. ↑ D Bateman; et al. (October 8, 2018), Electric Road Systems: a solution for the future (PDF), TRL, pp. 146–149
  13. 1 2 Léna Corot (August 30, 2023), "Vinci teste la recharge par induction et par rail sur autoroute", L'USINENOUVELLE.com
  14. ↑ Analysera förutsättningar och planera för en utbyggnad av elvägar, Swedish Transport Administration, February 2, 2021, pp. 21–23, 25–26, 54
  15. ↑ Daniel Boffey (April 12, 2018), "World's first electrified road for charging vehicles opens in Sweden", The Guardian
  16. ↑ Laurent Miguet (April 28, 2022), "Sur les routes de la mobilité électrique", Le Moniteur
  17. 1 2 Jean-Philippe Pastre (June 30, 2023), "L'APS d'Alstom bientôt testé sur les routes", TRM24
  18. ↑ PIARC (February 17, 2021), Electric Road Systems - PIARC Online Discussion, 34 minutes 34 seconds, 2 hours 36 minutes 51 seconds, archived from the original on December 22, 2021
  19. ↑ Martin G. H. Gustavsson, ed. (March 26, 2021), "Key Messages on Electric Roads - Executive Summary from the CollERS Project" (PDF), CollERS, p. 6, retrieved February 11, 2022
  20. ↑ European Commission (July 14, 2021), Proposal for a REGULATION OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL on the deployment of alternative fuels infrastructure, and repealing Directive 2014/94/EU of the European Parliament and of the Council
  21. ↑ Patrick Pélata; et al. (July 2021), Système de route électrique. Groupe de travail n°1 (PDF), archived from the original (PDF) on October 21, 2021
  22. ↑ "PD CLC/TS 50717 Technical Requirements for Current Collectors for ground-level feeding system on road vehicles in operation", The British Standards Institution , 2022, archived from the original on January 2, 2023, retrieved January 2, 2023
  23. 1 2 CENELEC Technical Standard 50717, CLC/TS 50717:2022 (E). Technical Requirements for Current Collectors for ground-level feeding system on road vehicles in operation
  24. ↑ Final draft: Standardization request to CEN-CENELEC on ‘Alternative fuels infrastructure’ (AFI II) (PDF), European Commission, February 2, 2022
  25. ↑ Matts Andersson (July 4, 2022), Regulating Electric Road Systems in Europe - How can a deployment of ERS be facilitated? (PDF), CollERS2 - Swedish German research collaboration on Electric Road Systems
  26. ↑ Deutsch, Volker (2003), Einsatzbereiche neuartiger Transportsysteme zwischen Bus und Bahn (PDF), Bergischen Universität Wuppertal, pp. 209–214
  27. ↑ "Partono i Lavori per la Rimozione delle Rotaie di Stream in via Mazzini", TriestePrima, 16 February 2012
  28. ↑ "Third-rail trams across the Garonne". Railway Gazette International . February 1, 2004. Retrieved May 2, 2008.
  29. ↑ "APS: Service-proven catenary-free tramway operations". Alstom. Archived from the original on 2020-11-29. Retrieved 2020-11-29.
  30. 1 2 Service Technique des Remontées Mécaniques et des Transports Guidés - Division TramWays (November 2011), ACCIDENTOLOGIE DES TRAMWAYS - Analyse des évènements déclarés année 2010 - évolution 2003-2010 (PDF)
  31. ↑ Service Technique des Remontées Mécaniques et des Transports Guidés - Division TramWays (October 19, 2021), Accidentologie « tramways » – Données 2020 (PDF)
  32. ↑ "Alstom transfers tram power supply technology to buses". Rail Insider. 26 September 2019. Archived from the original on 29 November 2020. Retrieved 29 November 2020.
  33. ↑ Patrick Dupart (February 11, 2022), Compatibility of an in-road Electric Road System with winter service operations (PDF), Alstom, PIARC
  34. ↑ Ameneiro, A. S. (2011-04-05). "Adiós a las catenarias en la Catedral". Diario de Sevilla (in Spanish). Seville. Retrieved July 16, 2018.
  35. ↑ "Zaragoza tram Line 1 enters service". Railway Gazette International . London. 2011-04-26. Retrieved 2018-07-16.
  36. ↑ Crespo Roig, María (2011-01-20). "CAF apuesta por que Zaragoza tenga un metro sin catenarias que funcione con la energía que recargue en las paradas". aragondigital.es (in Spanish). Zaragoza. Retrieved July 16, 2018.
  37. ↑ "Newcastle light rail to be Australia's first 'wire-free' system". 19 April 2017.
  38. ↑ "Newcastle Light Rail, Australia | Aurecon".
  39. ↑ 历经磨难 全球首个地面供电的100%低地板现代有轨电车项目终成正果
  40. ↑ 去颐和园、香山更方便啦！西郊线年底运营，还能和地铁换乘
  41. ↑ 中国首次引进现代有轨电车技术(图)
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.