Rubber-tyred metro

The first idea for rubber-tyred railway vehicles was the work of Scotsman Robert William Thomson, the original inventor of the pneumatic tyre. In his patent of 1846{{Cite patent|country= GB |number= 10990|gdate= 10 June 1846}} {{Dead link|date=July 2020}} he describes his 'Aerial Wheels' as being equally suitable for, "the ground or rail or track on which they run".{{Cite book

|title=The History of the Pneumatic Tyre

|chapter=1: Invention

|last=Tompkins

|first=Eric

|year=1981

|publisher=Dunlop Archive Project

|isbn=0-903214-14-8

|pages=[https://archive.org/details/historyofpneumat0000tomp/page/2 2–4]

|chapter-url=https://archive.org/details/historyofpneumat0000tomp/page/2

}} The patent also included a drawing of such a railway, with the weight carried by pneumatic main wheels running on a flat board track and guidance provided by small horizontal steel wheels running on the sides of a central vertical guide rail. A similar arrangement was patented by Alejandro Goicoechea, inventor of Talgo, in February 1936, patent ES 141056. In 1973, he built a development of that patent: 'Tren Vertebrado', Patent DE1755198; at Avenida Marítima, in Las Palmas de Gran Canaria.

During the World War II German occupation of Paris, the Metro system was used to capacity, with relatively little maintenance performed. At the end of the war, the system was so worn that thought was given as to how to renovate it. Rubber-tyred metro technology was first applied to the Paris Métro, developed by Michelin, which provided the tyres and guidance system, in collaboration with Renault, which provided the vehicles. Starting in 1951, an experimental vehicle, the MP 51, operated on a test track between Porte des Lilas and Pré Saint Gervais, a section of line not open to the public.

Line 11 Châtelet – Mairie des Lilas was the first line to be converted, in 1956, chosen because of its steep grades. That was followed by Line 1 Château de Vincennes – Pont de Neuilly in 1964, and Line 4 Porte d'Orléans – Porte de Clignancourt in 1967, converted because they had the heaviest traffic load of all Paris Métro lines. Finally, Line 6 Charles de Gaulle – Étoile – Nation was converted in 1974, to reduce train noise on its many elevated sections. Because of the high cost of converting existing rail-based lines, other lines were not converted, but the new Paris Métro Line 14, which opened in 1998, was built with the rubber-tyred system.

The first completely rubber-tyred metro system was built in Montreal, Quebec, Canada, in 1966. The trains of the Santiago and Mexico City Metros are based on those of the Paris Métro. A few more recent rubber-tyred systems have used automated, driverless trains. One of the first such systems, developed by Matra, opened in 1983 in Lille, and others have since been built in Toulouse and Rennes. Paris Metro Line 14 was automated from its beginning (1998), and Line 1 was converted to automatic operation in 2007–2011. The first automated rubber-tyred system in Kobe, Japan, opened in February 1981. It is the Port Liner, linking Sannomiya railway station with Port Island.

File:Ligne 1 du métro de Lille Métropole - Garage-atelier des Quatre Cantons (19).JPG tracks on the Lille Metro]]

Trains are usually in the form of electric multiple units. Just as on a conventional railway, the driver does not have to steer, with the system relying on some sort of guideway to direct the train. The type of guideway varies between networks. Most use two parallel roll ways, each the width of a tyre, which are made of various materials. The Montreal Metro, Lille Metro, Toulouse Metro, and most parts of Santiago Metro, use concrete. The Busan Subway Line 4 employs a concrete slab. The Paris Métro, Mexico City Metro, and the non-underground section of Santiago Metro, use H-Shaped hot rolled steel, and the Sapporo Municipal Subway uses flat steel. The Sapporo system and Lille Metro use a single central guide rail only.{{cite web

|url = http://www.urbanrail.net/as/sapp/sapporo.htm

|title = Sapporo Subway

|website = UrbanRail.Net

|access-date = 15 April 2008

|url-status = dead

|archive-url = https://web.archive.org/web/20080429201618/http://www.urbanrail.net/as/sapp/sapporo.htm

|archive-date = 29 April 2008

}}

On some systems, such those in Paris, Montreal, and Mexico City, there is a conventional {{Track gauge|sg|allk=on}} railway track between the roll ways. The bogies of the train include railway wheels with longer flanges than normal. These conventional wheels are normally just above the rails, but come into use in the case of a flat tyre, or at switches (points) and crossings. In Paris these rails were also used to enable mixed traffic, with rubber-tyred and steel-wheeled trains using the same track, particularly during conversion from normal railway track. The VAL system, used in Lille and Toulouse, has other sorts of flat-tyre compensation and switching methods.{{what|date=January 2022}}

On most systems, the electric power is supplied from one of the guide bars, which serves as a third rail. The current is picked up by a separate lateral pickup shoe. The return current passes via a return shoe to one or both of the conventional railway tracks, which are part of most systems, or to the other guide bar.

File:Sapporo subway rollers.jpg guide rail and flat steel roll ways]]

Rubber tyres have higher rolling resistance than traditional steel railway wheels. There are some advantages and disadvantages to increased rolling resistance, causing them to not be used in certain countries.

{{More citations needed section|date=April 2024}}

Compared to steel wheel on steel rail, the advantages of rubber-tyred metro systems are:

• Faster acceleration, along with the ability to climb or descend steeper slopes (approximately a gradient of 13%) than would be feasible with conventional rail tracks, which would likely need a rack instead.{{efn|Rubber-tyred wheels have better adhesion than traditional rail wheels. Nonetheless, modern steel-on-steel rolling stock using distributed-traction with a high proportion of powered axles have narrowed the gap to the performance found in rubber-tyred rolling stock.}}
• For example, the rubber-tyred Line 2 of the Lausanne Metro has grades of up to 12%.{{cite web |url=http://www.canada.com/montrealgazette/features/metro/story.html?id=c84a8361-0981-403c-b6df-8ce82fc71db2 |title=Sticking with rubber |work=Montreal Gazette |date=14 September 2005 |access-date=21 December 2011 |url-status=dead |archive-url=https://web.archive.org/web/20120517031404/http://www.canada.com/montrealgazette/features/metro/story.html?id=c84a8361-0981-403c-b6df-8ce82fc71db2 |archive-date=17 May 2012 }}
• Shorter braking distances, allowing trains to be signalled closer together.
• Quieter rides in open air (both inside and outside the train).
• Greatly reduced rail wear with resulting reduced maintenance costs of those parts.

The higher friction and increased rolling resistance cause disadvantages (compared to steel wheel on steel rail):

• Higher energy consumption.
• Worse ride, when compared with well-maintained steel-on-steel systems.{{Cite book|last=Harrison|first=Matthew C.|title=SAE Technical Paper Series|date=1 February 1974|chapter=Rubber Tire vs. Steel Wheel Tradeoffs|volume=1|chapter-url=https://www.sae.org/content/740228/|pages=740228|doi=10.4271/740228}}
• Possibility of tyre blow-outs - not possible in railway wheels.
• Higher cost of maintenance and manufacture.
• Normal operation generates more heat (from friction).
• Weather variance. (Applicable only to above-ground installations)
• Loss of the traction-advantage in inclement weather (snow and ice).{{efn|In order to reduce weather disruption, the Montreal Metro runs completely underground. On Paris Métro Line 6, upgrades of tyres (as used with cars) and special ribbed tracks have been tried out. The southernmost section of the Sapporo Municipal Subway Namboku Line is also elevated, but is covered by an aluminum shelter to reduce weather disruption.}}
• Same expense of steel rails for switching purposes, to provide electricity or grounding to the trains and as a safety backup.{{efn|In effect, there are two systems running in parallel so it is more expensive to build, install and maintain. This is in turn an advantage for conversions to this technology because it can be done with less service disruptions on an existing line, and allows to use more widespread railway components compared to VAL for example.}}
• Tyres that frequently need to be replaced, contrary to rails using steel wheels, which need to be replaced less often.{{efn|Since rubber tyres have higher wear rates, they need more frequent replacement, which makes them more expensive in the long run than steel wheelsets with higher first cost (that may be needed anyway as backup). Rubber tyres for guidance are needed.}}
• Tyres break down during use and turn into particulate matter (dust), which can be hazardous air pollution, also coating surrounding surfaces in dirty rubber dust.{{cite journal|title=Airborne Particulate Debris from Rubber Tires |last1=Pierson |first1=W. R. |last2=Brachaczek |first2=Wanda W. |journal=Rubber Chemistry and Technology |date=1 November 1974 |volume=47 |issue=5 |pages=1275–1299 |doi=10.5254/1.3540499}}

Although it is a more complex technology, most rubber-tyred metro systems use quite simple techniques, in contrast to guided buses. Heat dissipation is an issue as eventually all traction energy consumed by the train — except the electric energy regenerated back into the substation during electrodynamic braking — will end up in losses (mostly heat). In frequently operated tunnels (typical metro operation) the extra heat from rubber tyres is a widespread problem, necessitating ventilation of the tunnels. As a result, some rubber-tyred metro systems do not have air-conditioned trains, as air conditioning would heat the tunnels to temperatures where operation is not possible.

Automated driverless systems are not exclusively rubber-tyred; many have since been built using conventional rail technology, such as London's Docklands Light Railway, the Copenhagen metro and Vancouver's SkyTrain, the Hong Kong Disneyland Resort line, which uses converted rolling stocks from non-driverless trains, as well as AirTrain JFK, which links JFK Airport in New York City with local subway and commuter trains. Most monorail manufacturers prefer rubber tyres.

Rubber-tired systems are as follows, {{As of|2023|lc=yes}}:{{Citation needed|date=October 2024}}

{{Commons category}}{{div col|colwidth=22em}}

• Budd–Michelin rubber-tired rail cars
• Flat tire
• Guided bus
• Hybrid systems
• Medium-capacity rail system
• Micheline (railcar)
• Outline of tires
• Railway electrification system
• Rubber-tyred trams
• Tire (also spelled tyre)
• Toronto Zoo Domain Ride
• Tünel – a rubber-tyred funicular in Istanbul, Turkey
• VAL (Véhicule Automatique Léger)

{{div col end}}

{{noteslist}}

{{Reflist}}

• Bindi, A. & Lefeuvre, D. (1990). {{lang|fr|Le Métro de Paris: Histoire d'hier à demain,}} Rennes: Ouest-France. {{ISBN|2-7373-0204-8}}. {{in lang|fr}}
• Gaillard, M. (1991). {{lang|fr|Du Madeleine-Bastille à Météor: Histoire des transports Parisiens,}} Amiens: Martelle. {{ISBN|2-87890-013-8}}. {{in lang|fr}}
• [http://www.emdx.org/rail/metro/principeE.html Marc Dufour's "The principle behind the rubber-tired metro".] (English)

• [https://infovisual.info/transport Visual dictionary]
• [http://www.infovisual.info/05/050_en.html TRUCK (bogie)]
• [http://railsystem.net/rubber-tyred-metro-2/ Rail system]
• [https://web.archive.org/web/20030815044443/http://juts.janes.com/public/juts/index.shtml (Jane's) Urban Transit Systems]

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Category:Scottish inventions