Third rail

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Third rail at the West Falls Church Metro stop in Washington, D.C., electrified to 750 volts. The third rail is at the top of the image, covered by the white canopy above it. The two lower rails are the ordinary running rails; current from the third rail eventually returns to the power station through these.

A British Class 442 electric multiple unit powered by a third rail in Dorset.

Hamburg. U-Bahn (or Hochbahn) line U3 near Hoheluftbrücke Station. An early railway to use bottom-contact third rail.

Paris Metro. The guiding rails of the rubber-tyred lines are also current conductors. The current collector is between the pair of rubber wheels.

A third rail is a method of providing electricity to power a railway by means of continuous rigid conductor mounted alongside the railway track. It is used typically in a mass transit or rapid transit system, which has alignments in own corridors, fully or almost fully segregated from the outside environment. A list of lines or networks equipped with third rail is towards the end of this entry.

The third rail system of electrification is unrelated to the third rail used in dual-gauge railways.

[edit] History

Third-rail electric systems are, apart from on-board batteries, the oldest means of supplying electric power to trains on railways using own corridors, particularly in cities. Overhead power supply was initially almost exclusively used on tramway-like railways, though it also appeared slowly on mainline systems. (This statement describes the general trend; early particular cases may have been different.)

An experimental electric train using this method of power supply was developed by the German firm of Siemens & Halske and shown at the Berlin Industrial Exhibition of 1879. This pioneer electric railway had its third rail placed between running rails. At some early electric railways, though, one of the running rails could be the current conductor, as was the case of the 1883-opened Volk's Electric Railway in Brighton. Soon it was given an additional power rail in 1886 (the railway is still operating). The first railway to use the central third rail was the Bessbrook & Newry Tramway, opened in Ireland in 1885. The Giant's Causeway Tramway followed, retrofitted with outside third rail in c1887 (both closed). Also in the 1880s third-rail systems began to be used in public urban transport. Trams were first to benefit from it, but they used conductors built in conduit below the road surface (cf. Conduit current collection), and usually on selected parts of the networks. This was first tried in Cleveland (1884) and in Denver (1885) and later spread to many big tram networks (e.g. Manhattan, Chicago, Washington DC, London, Paris - all closed).

A third rail supplied power to the world's first electric underground railway, the City & South London Railway, which opened in 1890 (now part of the Northern Line of the London Underground). In 1893 the world's second third-rail powered city railway opened in Britain - the Liverpool Overhead Railway (closed 1956 and dismantled). The first US third-rail powered city railway in revenue use was the 1895-opened Metropolitan West Side Elevated, which soon became part of the Chicago 'L'. In 1901, Granville Woods, a prominent African-American inventor, was granted a U.S. Patent 687,098 , covering various proposed improvements to third rail systems. This has been cited to claim that he invented the third rail system of current distribution. However, by that time there had been numerous other patents for electrified third-rail systems, including Thomas Edison's U.S. Patent 263,132  of 1882, and third rails had been in successful use for over a decade, in installations including the rest of Chicago 'elevateds', as well as these in Brooklyn, New York (if not to mention the development outside the US). To what extent Woods' ideas were adopted is thus a matter of controversy.[1]

In Paris, in 1900, third rail appeared in the mainline tunnel connecting the Gare d'Orsay to the rest of the CF Paris-Orléans network. Mainline third rail electrification was later expanded to some suburban services in the French capital.

Top contact third rail (cf. below) seems to be the oldest form of power collection. Railways pioneering in using other, less hazardous types of third rail, were the New York Central Railroad on the approach to its NYC's Grand Central Terminal (1907 - another case of a third-rail mainline electrification) and the Hochbahn in Hamburg (1912) - both had bottom contact rail. However, the Manchester-Bury Line of the Lancashire & Yorkshire Railway tried the side contact rail (1917). These technologies appeared in wider use only at the turn of the 1920s and in the 1930s at, e.g., large-profile lines of the Berlin U-Bahn, the Berlin S-Bahn and the Moscow Metro.

In 1956 world's first rubber-tyred railway line was opened. This was Line 11 of Paris Metro. Power rail evolved into a pair of guiding rails required to keep the bogie in proper position on the new type of track. This solution was modified on the 1971-opened Namboku Line of Sapporo Subway, where a centrally placed guiding/return rail was used plus one power rail placed laterally as usually on steel rail railways (cf. photo).

The third rail technology at street tram lines has recently been revived in the new system of Bordeaux (2004). This is a completely new technology (cf. below).

Third rail, being the older of the two electric current supply methods, is by no means obsolete. There are, however, countries (particularly Japan, South Korea, India, Spain) more eager to adopt overhead wiring to their urban railways. But in the same time there were (and still are) many new third rail systems built elsewhere, including technologically advanced countries (i.e. Copenhagen Metro, Taipei Metro, Wuhan Metro). Bottom powered railways (it may be too specific to use the term 'third rail') are also usually these having rubber-tyred trains, no matter if it is a heavy metro (except two other lines of Sapporo Subway) or a small capacity people mover (PM). Practically the only type of railways where third rail is no longer used in new systems is regional and long distance rail, which require higher speeds and voltages.

With surface contact third (and fourth) rail systems a heavy "shoe" which is suspended from a wooden beam attached to the bogies (wheel units) collects power by sliding over the top surface of the electric rails. This view shows a class 313 train which operates primarily on Silverlink and First Capital Connect routes to the north and west of London.

The London Underground uses a four-rail system where both the conductor rails are live relative to the running rails (the rails used by the train's wheels) though the positive rail has twice the voltage of the negative rail. Arcs like this are quite normal and occur when the electric power collection "shoes" of a train that is motoring (ie: drawing power) reach the end of a section of electric power rail.

Third rail consisting of two strips of aluminium fitted to a steel rail.

[edit] Technical aspects

The third rail is usually located outside of the two running rails, but occasionally runs between them. The electricity is transmitted to the train by means of a sliding "shoe" (pick-up or contact shoe) which is held in contact with the rail. On many systems an insulating cover is provided above the third rail to protect employees working near the track; sometimes the shoe is designed to contact the side (called side running) or bottom (called bottom running) of the third rail, allowing the protective cover to be mounted directly to its top surface. When the shoe slides on top, it is referred to as "top running". When the shoe slides on the bottom it is not affected by the build-up of snow or leaves.

As with overhead wires, the return current on a third-rail system usually flows through one or both running rails, and leakage to ground is not considered serious. Where trains run on rubber tires, as on parts of the Paris Métro, Mexico City Metro and Santiago Metro, as well as on all of the Montréal Métro, live guide bars must be provided to feed the current. The return is affected through the rails of the conventional track between these guide bars (see rubber-tired metro). Another design, with a third rail (current feed, outside the running rails) and fourth rail (current return, half way between the running rails), is used by a few steel-wheel systems. The London Underground is the largest of these, see Fourth Rail.

In line M1 of the Milan underground, the third rail is used as the return electrical line (with potential near the ground) and the live electrical connection is made with a sliding block on the side of the car contacting an electrical bar located next to the railway (between the railway and the opposite direction railway) approximately 1 m (3') above the rail level. In this manner there are four rails. In the northern part of the line the more common overhead lines system is used.

The third rail is an alternative to electrified overhead lines that transmit power to trains by means of pantograph arms attached to the trains. Whereas overhead-wire systems can operate at 25 kV or more, using alternating current (AC), the smaller clearance around a live rail imposes a maximum of about 1200 V (Hamburg S-Bahn), and direct current (DC) is used. Trains on some lines or networks use both power supply modes (cf. below, "Compromise systems").

One method for reducing current losses (and thus increase the spacing of feeder/sub stations - a major cost in third rail electrification) is to construct the conductor rail of a hybrid aluminium/steel design (or composite conductor rail). The aluminium, which is a better conductor of electricity, combined with a running face of stainless steel, which gives better wear, aims to match the existing steel conductor rails.

There are currently several marketed ways of attaching the stainless steel to the aluminium. The oldest is a co-extruded method, where the stainless steel is extruded with the aluminium. This method has suffered, in isolated cases, from de-lamination (where the stainless steel separates from the aluminium); this is said to have been eliminated in the latest co-extruded rails. A second method is an aluminium core, upon which two stainless steel sections are fitted as a cap and linear welded along the centre line of the rail. Because aluminium has a higher coefficient of thermal expansion than steel, the aluminium and steel must be positively locked to provide a good current collection interface. A third method rivets aluminum bus strips to the web of the steel rail. The photo on the right depicts such a rail.

[edit] Advantages of third rail

Cost

Third-rail systems are cheaper to install than overhead wire systems, less prone to weather damage (other than flooding and icing, which cause major problems), and better able to fit into areas of reduced vertical clearance, such as tunnels and bridges. In many countries they were perceived as key means of reducing construction costs of tunnels, hence their popularity at underground railways.

Visual appeal

Third-rail systems cause less visual intrusion: they do not need overhead lines, which some people perceive as unsightly. Singapore, for example, has banned overhead wires on lines outside tunnels. Urban street railways have been built, for example in Washington DC, London, and Brussels, that carry the conductor rail within a slotted box in the center of the track (conduit current collection), primarily to avoid unsightly overhead wires and poles. These resemble the cable slot for a street cable car as seen in San Francisco. Rather than a mechanical grip, an insulated electrical pickup extends into the slot.

Robustness

Third-rail systems are more robust than overhead line systems, as the conductor rail is able to take higher mechanical forces than the contact wire of an overhead line system. The shoegear on a train is designed to shear off if hits the conductor rail too hard, but as a train has many sets of shoegear, it is able to continue its journey. By contrast a pantograph is more likely to get tangled up in the overhead wires and not be able to continue its journey.

Maintenance access

The safety hazard third rail provokes has also its other face: easier access for maintenance work.

Compatibility

Many railways use third rail and DC power, even where overhead lines would otherwise be practical, due to the high cost of retrofitting. Every expansion of such system must cope with the problem of compatibility. It usually leads for the choice of already existing technology.

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[edit] Disadvantages of third rail

Third-rail systems have a number of problems and disadvantages, including:

The examples and perspective in this article or section may not represent a worldwide view of the subject. Please improve this article or discuss the issue on the talk page.

Safety

An unguarded electrified rail is a safety hazard, and some people have been killed by touching the rail or by stepping on it while attempting to cross the tracks. However, such incidents are usually the result of carelessness on the part of the victim. The principal hazard is probably associated with level crossings. While their number on third rail lines is normally reduced to none, they still occur at some systems, particularly on rural and suburban portions of the network. One notable example of a Metro line is the outer end of the present Brown Line of Chicago 'L', running on street level in a densely populated neighborhood. The conductor is discontinued in the level crossing area. Pedestrians may be discouraged from trespassing into railway area by means of perforated panels difficult to step on ('cattle-cum-trespass guards'). They are laid between rails alongside the road.

There are urban legends that people have died while urinating on the third rail (the urine stream supposedly completes an electrical circuit that electrocutes the victim); a non-continuous stream has been proven by MythBusters to be unable to conduct electricity [2].

A photo of the third rails used on the BART system. Notice how the rail changes location relative to the train upon entering the station for safety reasons (see article for more info).

• A new tramway system in Bordeaux, France surmounts the safety problem by using a third rail divided into insulated segments only a few metres long. Each segment is live only while completely covered by a tram, so there is no risk of a person or animal coming into contact with a live rail (see Third-rail power for trams for more information). This system would not be suitable for higher speeds, and the cost of breaking the live rail into short sections is considerable. This system was developed mainly for aesthetic reasons, to avoid overhead wires in front of the town hall.

• As the above example shows, this factor is highly dependent on the specific transit system's implementation. As another example, the BART system in the San Francisco Bay Area uses sturdy sheaths to cover its third rails and always places the rail on the further side of the track away from where passengers would normally be. As a result, some stations have the third rail on the left relative to the train's motion, while others have it on the right. If someone falls on the tracks, this allows them to return safely to the platform without the danger of stepping on the third rail or crawl under the platform into a special "Safety Area" if a train is too close to climb back up safely. The New York City Subway, Washington Metro and Long Island Rail Road follow similar procedures.

Limited capacity

A relatively low voltage is necessary in a third-rail system — otherwise, electricity would arc from the rail to the ground or the running rails — but the resulting higher current causes more proportional voltage drop per mile, meaning that electrical feeder sub-stations have to be set up at frequent intervals along the line (generally no more than 10 miles or 16 km apart), increasing operating costs. The low voltage also means that the system is prone to overload, which makes such systems unsuitable for freight or high-speed trains demanding high amounts of power. These limitations of third-rail systems have largely restricted their use to mass transit systems. Even higher voltages - such as 750 V DC third rail - as used on many hundreds of suburban railway route miles across south and southeast England, and the 1000 V DC used on the BART system, with just over 100 miles of track, are restricted to this area of railroad transport. Capacity is also limited by speed restrictions – 160 km/h (100 mph) is considered to be the maximum speed at which a contact shoe can reliably collect power^{[citation needed]}.

By comparison, overhead wires can provide 25kV or even 50kV, and can take roughly ten times the power.

Infrastructure restrictions

Junctions and other pointwork make it necessary to leave gaps in the live rail at times, as do level crossings. This is not usually a problem, as most third-rail rolling stock has multiple current collection shoes along the length of the train, but under certain circumstances it is possible for a train to become "gapped" - stalled with none of its shoes in contact with the live rail. When this happens, it is usually necessary for the train to be shunted back onto a live section either by a rescue locomotive or another service train, although in some circumstances it is possible to use jumper cables to temporarily hook the train's current collectors to the nearest section of live rail. Especially given that gapping tends to happen at complex, important junctions, it can be a major source of disruption. On the Chicago Transit Authority system, the jumper cables are known as stingers; they are insulated poles with a wired contact that may be manually pressed against contact shoes to restart a gapped train. Again, such problems are very much implementation-specific, and transit systems around the world have managed to work around these problems. The aforementioned BART system has numerous sections of switching track, especially around its transfer stations, where the third rail is alternately on the right- and left-hand sides. No problems have arisen from the use of this system in years. On the Metro-North Railroad and the Long Island Rail Road (including Pennsylvania Station which is owned by Amtrak), the safety cover decreases the structure gauge and in turn the loading gauge.

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Inefficient contact

Fallen leaves, snow and other debris on the conductor rail can reduce the efficiency of the contact between the conductor rail and the pickup shoes, leaving trains stalled because of the lack of power. However, the bottom-contact third rail, as used on the Metro-North Railroad (see Technical aspects above), and numerous other transit systems including the Docklands Light Railway in London and the Market-Frankford Line in Philadelphia, is highly resistant to this problem.

Basically, older systems adopted top-contact third rail before they realised that there would be problems with leaves, etc., while newer systems have learned from this mistake and use side or bottom contact. It should be pointed out, however, that many relatively new systems, particularly in North America, such as the TTC in Toronto, use top-covered top-contact third rails on above-ground portions of its subway system; rarely is the system delayed by electrical problems even after heavy snows. Rather, problems generally arise from other aspects of the system (frozen switches for example) long before snow interferes significantly with electrical pickup. BART system contains almost 70 miles of above-ground track and experiences few, if any, problems as a result of weather. In addition, systems that are completely covered (i.e. underground) are obviously immune to the problem.

[edit] Compromise systems

There are and have always been several systems in which third rail has been used for part of the system, and overhead lines for the remainder. These exist sometimes because of the connection of separately-owned railways using the different systems, or because of local ordinances.

In New York City, electric trains that must use third rail leaving Grand Central Terminal on the former New York Central Railroad (now Metro-North Railroad) switch to overhead lines at Pelham when they need to operate out onto the former New York, New Haven and Hartford Railroad (now Metro North's New Haven Line) line to Connecticut. The switch is made "on the fly" controlled from the engineer's position.

The P32AC-DM is used on Amtrak and Metro North lines entering Pennsylvania Station (New York City) due to a prohibition on diesel emissions in tunnels entering the city. This locomotive uses both an onboard diesel engine or from a third rail carrying 750 volts of direct current and can seamlessly transition between the two modes while underway.

Several types of British trains operate on both overhead and third rail systems, including class 313, 319, 325 and 373 Eurostar trains.

In Manhattan, New York City, and in Washington, D.C., local ordinances required electrified street railways to draw current from a third rail and return the current to a fourth rail, both installed in a continuous vault underneath the street and accessed by means of a collector that passed through a slot between the running rails. When streetcars on such systems entered territory where overhead lines were allowed, they stopped over a pit where a man detached the collector (plow) and the motorman placed a trolley pole on the overhead. Some sections of the former London tram system also used the conduit current collection system, and here too there were some tramcars which could collect power from both overhead and under-road sources.

The Blue Line of Boston's MBTA uses third rail electrification from the start of the line downtown to Airport, where it switches to overhead catenary for the remainder of the line to Wonderland. Dual power supply method was also common on these few US interurban railways that made use of third rail (all closed). Thanks to being able to run under wires, they could reach downtown by using streetcar (trolley) infrastructure.

The older lines in the west of the Oslo T-bane system were built with overhead lines (some since converted to third rail) while the eastern lines were built with third rail. Trains operating on the older lines can operate both with third rail and overhead lines. To mitigate investment costs, the Rotterdam Metro, basically a third-rail powered system, has been given some outlying branches built on surface as light rail (called 'Sneltram' in Dutch), with numerous level crossings protected with barriers and traffic lights. These branches have overhead wires. Similarly, in Amsterdam one 'Sneltram' route goes on Metro tracks and passes to surface alignment in the suburbs, which it shares with standard trams. In most recent developments, the RandstadRail project also requires Rotterdam Metro trains to run under wires on their way along the former mainline railway to The Hague.

In Chicago, the Yellow Line, also known as the Skokie Swift, operates for most of its distance with third rail, switching to overhead catenary before reaching the end of the line at the Dempster Street station. As of December 2005, the rest of the Skokie Swift line is now all third rail, since cars needed to run this line were always having to be retrofit with pantographs. This particular line was once a part of the Chicago, North Shore and Milwaukee interurban line.

The Eurostar uses overhead electrical power (at 25 kV AC) in the Channel Tunnel and along the CTRL, with only a pantograph height change on exit from the Chunnel. In the south-east a transition is made on-the-fly to 750 V DC for the remainder of the journey through the London suburbs, on the standard commuter lines into Waterloo using the third rail system. From 2007, upon completion of the Channel Tunnel Rail Link, there will be overhead electricity all the way into London.

Also in London, the North London Line changes its power supply several times between Richmond and North Woolwich. The cross-city Thameslink service runs on Southern Region third rail from Farringdon station southwards and on overhead line northwards from Farringdon up to Bedford: this change-over is made while stationary.

The newly built tramway in Bordeaux (France) uses a novel system with a third rail in the center of the track. The third rail is separated into 8 m (26 ' 3 ") long conducting and 3 m (9 ' 10 ") long isolation segments. Each conducting segment is attached to an electronic circuit which will make the segment live once it lies fully beneath the tram (activated by a coded signal sent by the train) and switch it off before it becomes exposed again. This system (called "Alimentation par Sol" (APS), meaning "current supply via ground") is used in various locations around the city but especially in the historic centre: elsewhere the trams use the conventional overhead lines, see also ground-level power supply. In summer 2006 it was announced that two new French tram systems would be using APS over part of their networks. These will be Angers and Reims, with both systems expected to open around 2009 / 2010.

Interestingly, the Japanese urban rail systems, frequently running reciprocally to other company's networks, do not use trains with dual power supply modes. In case of Metros, it was the characteristics of pre-existing outbound railways that determined the technical design of new lines, which were to be interoperated. Hence the narrow gauge and overhead power supply on many Tokyo Subway lines.

[edit] Conversions from and to third rail

Despite various technical possibilities of operating stock with dual power collecting modes, the desire to achieve full compatibility of entire networks seems to have been the decisive cause of conversions from third rail to overhead supply (or vice versa).

Selected suburban corridors in Paris, focusing at Gare Saint-Lazare, Gare des Invalides (both CF Ouest) and Gare d'Orsay (CF PO), were electrified from 1924, 1901, 1900 respectively. They all changed to overhead wires by stages after they became part of a wide scale electrification project of the SNCF network (the 1960s-70s).

In Manchester area, the aforementioned Bury Line (originally L&YR) was first electrified with overhead wires (1913), then changed to third rail (1917, cf. Railway electrification in Great Britain) and again in 1992 to overhead wires in the course of its adaptation for the Manchester Metrolink. Trams in city centre streets, carrying collector shoes projecting from their bogies, were considered too dangerous for pedestrians and motor traffic to attempt dual-mode technology (in Amsterdam and Rotterdam Sneltram vehicles go out to surface in suburbs, not in busy central areas). The same thing happened to the West Croydon - Wimbledon Line in Greater London (originally electrified by the Southern Railway) when Croydon Tramlink was built (opened 2000).

Three lines of five making up the core of Barcelona Metro network changed to overhead power supply from third rail. This operation was also done by stages and completed in 2003.

Quite the opposite thing took place in London. The South London Line of the LBSCR network (between Victoria and London Bridge Stations) was electrified with catenary in 1909 - the system was later extended to Crystal Palace, Coulsdon North and Sutton. In the course of mainline third rail electrification in south-east England, the lines were converted accordingly by 1929.

The first overhead electric trains appeared on the de:Hamburg-Altonaer Stadt- und Vorortbahn in 1907. Thirty years later, the mainline railway operator, Deutsche Reichsbahn, influenced by the success of the third-rail Berlin S-Bahn, decided to switch what was now called Hamburg S-Bahn to third rail. The process began in 1940 and was not finished until 1955.

In 1976-1981 the third-rail Viennese U-Bahn U4 Line substituted the Donaukanallinie and Wientallinie of the Stadtbahn, built c1900 and first electrified with overhead wires in 1924. This was part of a big project of consolidated U-Bahn network construction. The other electric Stadtbahn line, whose conversion into heavy rail stock was rejected, still operates under wires with light rail cars (as U6), though it has been thoroughly modernised and significantly extended. As the platforms on the Gürtellinie were not suitable for raising without much intervention into historic Otto Wagner's station architecture, the line would anyway remain incompatible with the rest of the U-Bahn network. Therefore an attempt of conversion to third rail would have been pointless. In Vienna, paradoxically, the wires were retained for aestetic (and economic) reasons.

The already discussed Skokie Swift of Chicago 'L' changed to third rail in 2004, to make it compatible with the rest of the system.

The reasons for building the overhead powered Tyne & Wear Metro network roughly on lines of the long-gone third-rail Tyneside Electrics system in Newcastle area are likely to have roots in economy and psychology rather than in the pursue of compatibility. At the time of the Metro opening (1980) there were no third-rail light rail vehicles on the market and the latter technology was confined to much more costly heavy rail stock. Also the far-going change of image was desired: the memories of the last stage of operation of the Tyneside Electrics were far from being favourable. This was the construction of the system from scratch after eleven years of ineffective diesel service.

[edit] List of Systems using third rail

Third rail railways predominantly operate in urban contexts. Notable exceptions are (or were) mainline electrics of the former Southern Region in England and a few interurban railways in the US. In Europe top contact third rail tends to be limited to early electrified urban railways (the current conductor is normally left naked on top), contrary to North America where it usually has a protecting cover. Obviously considered safe enough, the covered top contact conductor also appeared at most North American systems built relatively recently. Modern European systems predominantly make use of bottom or side contact power rails.

It is also interesting to realise the existence of numerous urban rail systems, including these running mostly in tunnels, which do not use third rail at all. Such systems can be found in Asia, which may have been influenced by the overhead power supply formula followed by Tokyo Metro after 1960. All South Korean systems use overhead wires (or rigid conductors), as do most modern mainland Chinese Metros. In Europe all significant Spanish systems now have overhead power supply. Modern Latin America urban rail also uses overhead wires, though with some important exceptions.

Special group of bottom power supplied railways are rubber-tyred systems. In fact, it may be difficult to classify them beyond any doubt. They may be trains, but are they still railways? And do they still have 'third' rails? Despite doubts, such guided systems have been included in the list below.

The list does not include conduit system trams (trolleys), quite popular in some countries, but none survive.

NOTES:

t/c - top contact; others have bottom or side contact power rails (or rail type not known);

gr/c - combined with guiding rail on rubber-tyred systems (including light metros such as VAL)

[edit] Europe

United Kingdom

Former:

• Giant's Causeway Tramway
• Bessbrook & Newry Tramway (t/c)
• Liverpool Overhead Railway (t/c)
• Manchester Victoria - Bury (by the L&YR) (side contact)
• Tyneside Electrics (t/c)

[edit] Asia

Japan

• Sapporo Chikatetsu - Namboku Line: rubber-tyred with central guiding/return rail and lateral power rail (t/c); Tōzai and Tōhō Lines: rubber-tyred with o/h power supply, lateral return rail and a central guiding rail
• Nagoya Chikatetsu - Higashiyama, Meijō, Meikō Lines (t/c, covered)
• Osaka Chikatetsu - except Sakaisuji, Nagahori-tsurumi-ryokuchi and Imazatosuji Lines (t/c, covered)
• Kinki Nippon Tetsudō - Higashi-Ōsaka and Keihanna Lines (all workings run reciprocally to Osaka Subway's Chūō Line) (t/c, covered)
• Kita-Ōsaka Kyūkō Tetsudō (all workings run reciprocally to Osaka Subway's Midōsuji Line) (t/c, covered)

Former:

• Shin'etsu Line at Usui Pass (Yokokawa-Karuizawa) - mainline system
• Komaki Peachliner (rubber-tyred, but power supply separate from guiding rail)

[edit] Africa

[edit] North America

United States

Former:

• World's Columbian Exhibition (Chicago, 1893) railway (t/c)
• Pennsylvania Railroad, suburban network New York - New Jersey (t/c, covered)
• Albany & Hudson Railroad (t/c)
• Baltimore Belt Line, Baltimore & Ohio Railroad
• Scioto Valley Traction Co. (Ohio) (t/c?)
• Oneida Railway (NY Central RR)
• Detroit River Tunnel (Detroit - Windsor), Michigan Central Railroad
• Michigan Rly.: Grand Rapids - Kalamazoo and branch lines
• Central California Traction Co. (Sacramento area)
• Sacramento Northern Railway (t/c)
• Aurora Elgin & Chicago Railroad (t/c)
• Key System - on San Francisco-Oakland Bay Bridge (t/c, covered)
• Jacksonville VAL (gr/c)

[edit] South America

[edit] See also

• Conduit current collection
• Ground level power supply
• Rubber-tired metro
• Third-rail power for trams
• List of rapid transit systems
• List of suburban and commuter rail systems
• Railway electrification in Great Britain

[edit] External links

Wikimedia Commons has media related to:

Third rail

• Thomas Edison's third rail patent (1882)
• Lightrail without wires - Paper on Bordeaux' new Tram with street level third rail (by the Transportation Research Board of the National Academies)

• Details of the UK 3rd/4th rail design.
• The "third rail" A short history.