Rubber-tyred metro in the context of "MP 05"

Rapid transit, mass rapid transit (MRT) or rail rapid transit (RRT) and commonly referred to as metro, is a type of high-capacity public transport that is generally built in urban areas. A grade separated rapid transit line below ground surface through a tunnel can be regionally called a subway, tube, metro or underground. They are sometimes grade-separated on elevated railways, in which case some are referred to as el trains – short for "elevated" – or skytrains. A common alternative term for rapid transit in North America is heavy rail. Rapid transit systems are usually electric railways that, unlike buses or trams, operate on an exclusive right-of-way, which cannot be accessed by pedestrians or other vehicles.

Modern services on rapid transit systems are provided on designated lines between stations typically using electric multiple units on railway tracks. Some systems use guided rubber tires, magnetic levitation (maglev), or monorail. The stations typically have high platforms, without steps inside the trains, requiring custom-made trains in order to minimize gaps between train and platform. They are typically integrated with other public transport and often operated by the same public transport authorities. Some rapid transit systems have at-grade intersections between a rapid transit line and a road or between two rapid transit lines.

Rapid transit, mass rapid transit (MRT) or rail rapid transit (RRT) and commonly referred to as metro, is a type of high-capacity public transport that is generally built in urban areas. A grade separated rapid transit line below ground surface through a tunnel can be regionally called a subway, tube, metro or underground. They are sometimes grade-separated on elevated railways, in which case some are referred to as elevated, el or L trains – short for "elevated" – or skytrains. A common alternative term for rapid transit in North America is heavy rail. Rapid transit systems are usually electric railways that, unlike buses or trams, operate on an exclusive right-of-way, which cannot be accessed by pedestrians or other vehicles.

Modern services on rapid transit systems are provided on designated lines between stations typically using electric multiple units on railway tracks. Some systems use guided rubber tires, magnetic levitation (maglev), or monorail. The stations typically have high platforms, without steps inside the trains, requiring custom-made trains in order to minimize gaps between train and platform. They are typically integrated with other public transport and often operated by the same public transport authorities. Some rapid transit systems have at-grade intersections between a rapid transit line and a road or between two rapid transit lines.

The MP 89 (French: Métro Pneu appel d'offres de 1989; English: Rubber-tyred metro ordered in 1989) is a rubber tired variant of electric multiple units used on the Paris Métro. Designed by Roger Tallon, two types were built by Alstom for service on Lines 4 and 14, and has begun service on Line 6. The trains on Line 1 were moved to Line 4 between 2011 and 2013 to replace the older MP 59s, though only 48 trains are used for revenue service. The remaining four trains are stored either at Montrouge or Saint Ouen as operational spares.

The MP 59 (French: Métro Pneu appel d'offres de 1959; English: Rubber-tyred metro ordered in 1959) was a rubber-tyred variant of electric multiple units used on the Paris Métro system in service from 1963 to 2024. Manufactured by a consortium between CIMT-Lorraine (body), Jeumont-Schneider (control circuits), Alsthom and CEM (motors), they were first introduced in 1963 when the busiest routes of Lines 1 and 4 were converted to rubber-tyred pneumatic operation. The trains worked on Line 1 between 1963 and 2000, Line 4 between 1966 and 2012, and Line 11 between 1995 and 2024. By the time of their retirement in June 2024, the MP 59 trains (along with the Sprague-Thomson) were among the oldest trains still in use on any metro system in the world, at 61 years old.

Line A (Ligne A) is a line on the Lyon Metro that runs between Perrache and Vaulx-en-Velin–La Soie. It was constructed using the cut-and-cover method, and went into service on 2 May 1978. It, together with Line B, were the inaugural lines of the Lyon Metro. An extension of Line A from Laurent Bonnevay–Astroballe to Vaulx-en-Velin–La Soie opened in 2007. The line currently serves 14 stations, and is 9.2 kilometres (5.7 mi) long. Line A trains run on tires rather than steel wheels; it is a rubber-tired metro line.

A roll way or running pad is the pad placed on a concrete slab or on the ties on the outside of the 1,435 mm (4 ft 8+1⁄2 in) conventional track along both running rails of a rubber-tyred metro or along the unconventional track of a tram. The rubber-tyred wheels roll directly on the roll ways.

• With a conventional track:
  • The ones of the Montreal Metro are precast concrete on a concrete slab.
  • The ones of the Paris Métro are H-steel on ties.
  • The ones of the Mexico City Metro are H-steel.
  • The ones of the Santiago Metro are precast concrete below ground and H-steel above ground.
  • The ones of the Lausanne Métro Line M2 are H-steel.
  • The ones of the Lyon Metro (lines A, B and D) are H-steel.
• Without a conventional track:
  • The ones of the Lille Metro are precast concrete.
  • The ones of the Toulouse Metro are precast concrete.
  • The ones of the Sapporo Municipal Subway are flat steel with a central guide rail.
  • Busan Subway Line 4 runs directly on a concrete slab between guide bars.
  • Many people mover systems, such as Crystal Mover, run directly on concrete slabs or other surfaces between guide bars.
  • Some guided buses, rubber-tyred trams, such as Translohr and Bombardier Guided Light Transit, use concrete slabs while being guided by a single central rail.

Guide bars, or guiding bars are rubber-tyred metro systems that incorporate 1,435 mm (4 ft 8+1⁄2 in) standard gauge track. They have angle irons as outside of the two roll ways.

The Busan Subway Line 4 lacks a rail track, and has I-beams installed as guide bars.