MF 88


The MF 88 is a steel-wheel variant of electric multiple units used on Paris's Métro system. RATP contracted a consortium of manufacturers, with Ateliers du Nord de la France in charge of the project.
They were built following successful tests of a prototype train-set called the "BOA", derived from the MF 77, which tested new features such as open gangway connections between cars to improve passenger distribution and special bogies to reduce friction 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 was also the last model not newly built with automatic announcements and with user-activated doors.
The MF 88 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. This design was causing excessive wear on the track; this because of a design flaw in the chassis, where each intermediate bogie only has one axle, similar to a typical car, bus, some rubber-tyred trains, or certain railbuses, but unusual for a more “standard” railcar, especially one powered by electricity. The high rate of wear-and-tear of the train-sets has made maintenance much more expensive than expected.

Technical specifications

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.