Rubber-tyred metro

The vehicles have wheels with rubber tires that run on a roll way inside guide bars for traction.

Traditional, flanged steel wheels running on rail tracks provide guidance through switches and act as backup if tyres fail.

[1] The first idea for rubber-tyred railway vehicles was the work of Scotsman Robert William Thomson, the original inventor of the pneumatic tyre.

During the World War II German occupation of Paris, the Metro system was used to capacity, with relatively little maintenance performed.

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.

Finally, Line 6 Charles de Gaulle – Étoile – Nation was converted in 1974 to reduce train noise on its many elevated sections.

[4] On some systems, such those in Paris, Montreal, and Mexico City, there is a conventional 1,435 mm (4 ft 8+1⁄2 in) standard gauge railway track between the roll ways.

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.