The MF 88 (; ) is a steel-wheel variant of

electric multiple unit An electric multiple unit or EMU is a multiple-unit train consisting of self-propelled carriages using electricity as the motive power. An EMU requires no separate locomotive, as electric traction motors are incorporated within one or a number o ...

s used on

Paris Paris () is the Capital city, capital and List of communes in France with over 20,000 inhabitants, largest city of France. With an estimated population of 2,048,472 residents in January 2025 in an area of more than , Paris is the List of ci ...

's Métro system. RATP contracted a consortium of manufacturers, with

Ateliers du Nord de la France Alstom Crespin, formerly Bombardier Transport France and ANF Industrie, is a French rolling stock manufacturer based at Crespin, in Hauts-de-France region, France. The company was acquired by Bombardier Transportation in 1989, then by Alstom in 2 ...

in charge of the project. They were built following successful tests of a

prototype A prototype is an early sample, model, or release of a product built to test a concept or process. It is a term used in a variety of contexts, including semantics, design, electronics, and Software prototyping, software programming. A prototype ...

train-set called the "BOA", derived from the

MF 77 The MF 77 (; ) is a steel-wheeled variant of the rolling stock used on the Paris Métro. First used in 1978, it now runs on Lines 7, 8, and 13. Unlike previous models, the MF 77 was designed for travel into the immediate suburbs of Pari ...

, which tested new features such as

open gangway A gangway connection or corridor connection is a flexible connector fitted to the end of a railway coach, enabling passengers to move between coaches without danger of falling from the train. Origins: Coaches in British and American railways Th ...

connections between cars to improve passenger distribution and special

bogie A bogie ( ) (or truck in North American English) comprises two or more Wheelset (rail transport), wheelsets (two Railroad wheel, wheels on an axle), in a frame, attached under a vehicle by a pivot. Bogies take various forms in various modes ...

s to reduce

friction Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. Types of friction include dry, fluid, lubricated, skin, and internal -- an incomplete list. The study of t ...

caused by the sharp curves found in the Métro network. The MF 88 introduced a number of innovations in its time, including AC induction motors and an on-board computer system using a new standard integrated computing architecture. It is planned for the MF 19 CC rolling stock to replace the MF 88 in 2026.

Design

Carrying on the features of the BOA, a total of nine MF 88 train-sets were built, which have only ever operated on Line 7bis in a three-car formation. It was the first model with AC motors, supplied by GEC Alsthom, as opposed to DC and with interconnecting gangways. The MF 88 was also the first to adopt a new computing architecture, developed by TechnicAtome, over relay-based systems used in older Paris Metro rolling stock. It also introduced an independent-wheeled steering axle design, but this turned out to cause several problems for RATP and was not adopted in subsequent Paris Metro rolling stock. It was also the last model not newly built with automatic announcements and with user-activated doors (all subsequent models, as well as more recently the MF 77s on Line 13, have had all doors open at once). The high rate of wear-and-tear of the train-sets has made maintenance much more expensive than expected. The independent-wheeled steering axle design was found to be problematic and was causing excessive wear on the track. This is because of a design flaw in the

chassis A chassis (, ; plural ''chassis'' from French châssis ) is the load-bearing framework of a manufactured object, which structurally supports the object in its construction and function. An example of a chassis is a vehicle frame, the underpart ...

, where each intermediate bogie only has one

axle An axle or axletree is a central shaft for a rotation, rotating wheel and axle, wheel or gear. On wheeled vehicles, the axle may be fixed to the wheels, rotating with them, or fixed to the vehicle, with the wheels rotating around the axle. In ...

, similar to a typical car, bus, some rubber-tyred trains (although the rubber-tyred lines of the Paris Métro use the typical 2-axle bogies), or certain

railbuses A railbus is a lightweight passenger railcar with an automotive engine. It shares many aspects of its construction with a bus, typically having a bus (original or modified) body and four wheels (2 axles) on a fixed base instead of on bogies. O ...

, but unusual for a more “standard” railcar, especially one powered by electricity.STIF - ''Schéma directeur du matériel métro''
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Technical specifications

* Manufacturers: Alstom, GEC Alsthom, Faiveley,

Renault Renault S.A., commonly referred to as Groupe Renault ( , , , also known as the Renault Group in English), is a French Multinational corporation, multinational Automotive industry, automobile manufacturer established in 1899. The company curr ...

, ANF * Electric source: * Traction:

Gate turn-off thyristor A gate turn-off thyristor (GTO) is a type of high-power (e.g. 1200 V AC) thyristor that unlike a normal thyristor is fully controllable and can be turned On and Off by their gate lead. It was invented by General Electric. Device descrip ...

(GTO) * Power: 2

motors An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy. Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power gene ...

per motor coach with each, total per train * Maximum operating speed: , currently reduced to due to rolling stock's condition * Bogies: Bi-directional * Length:

Formations

As of 1 September 2022, eight MF 88 trainsets were in service and were formed as shown below. One trainset was scrapped in 2013. As of 1 March 2022, eight trainsets are allocated to Pré Saint-Gervais depot for use on Line 7bis.

References

{{Paris transport network Paris Métro rolling stock Paris Métro line 7bis 750 V DC multiple units Alstom multiple units Electric multiple units of France Train-related introductions in 1993