The MI 84 (French: ''Matériel d'Interconnexion de 1984'', English: ''interconnection rolling stock of 1984''), also known as the Class Z 8100 is a
dual-voltage 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 numbe ...
trainset that is operated on
line B of the
Réseau Express Régional
The Réseau Express Régional ( en, Regional Express Network), commonly abbreviated RER (), is a hybrid commuter rail and rapid transit system serving Paris and its Île-de-France, suburbs. It acts as a combined city-centre underground rail syst ...
(RER), a hybrid
suburban commuter and
rapid transit
Rapid transit or mass rapid transit (MRT), also known as heavy rail or metro, is a type of high-capacity public transport generally found in urban areas. A rapid transit system that primarily or traditionally runs below the surface may be c ...
system serving
Paris
Paris () is the capital and most populous city of France, with an estimated population of 2,165,423 residents in 2019 in an area of more than 105 km² (41 sq mi), making it the 30th most densely populated city in the world in 2020. S ...
and its
Île-de-France
, timezone1 = CET
, utc_offset1 = +01:00
, timezone1_DST = CEST
, utc_offset1_DST = +02:00
, blank_name_sec1 = Gross regional product
, blank_info_sec1 = Ranked 1st
, bla ...
suburbs.
The 73 four-car trains were built by a
consortium
A consortium (plural: consortia) is an association of two or more individuals, companies, organizations or governments (or any combination of these entities) with the objective of participating in a common activity or pooling their resources for ...
of
French
French (french: français(e), link=no) may refer to:
* Something of, from, or related to France
** French language, which originated in France, and its various dialects and accents
** French people, a nation and ethnic group identified with Franc ...
manufacturers
Alsthom
Alstom SA is a French multinational rolling stock manufacturer operating worldwide in rail transport markets, active in the fields of passenger transportation, signalling, and locomotives, with products including the AGV, TGV, Eurostar, Avelia ...
and
ANF Industrie
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 20 ...
(which would be purchased by
Bombardier in 1989 before the end of the deliveries). The final assembly of the trains was performed at Alstom's
Valenciennes
Valenciennes (, also , , ; nl, label=also Dutch, Valencijn; pcd, Valincyinnes or ; la, Valentianae) is a commune in the Nord department, Hauts-de-France, France.
It lies on the Scheldt () river. Although the city and region experienced a s ...
factory and ANF's
Crespin factory between 1985 and 1990.
The design of the MI 84 was derived from the earlier
MI 79
The MI 79 (French: ''Matériel d'Interconnexion de 1979'', English: ''interconnection rolling stock of 1979''), also known as the Class Z 8100 is a Multi-system (rail), dual-voltage electric multiple unit trainset that is operated on RER B, line ...
built for the RER B, but with modifications to make it better suited for the
RER A
RER A is one of the five lines in the Réseau Express Régional (English: Regional Express Network), a hybrid commuter rail and rapid transit system serving Paris, France and its suburbs. The line crosses the region from east to west, with all t ...
line. The introduction of double-decker trainsets on the RER A allowed the MI 84 trains to be shifted to the RER B by 24 February 2017.
History
In the late 1980s, the
RER A
RER A is one of the five lines in the Réseau Express Régional (English: Regional Express Network), a hybrid commuter rail and rapid transit system serving Paris, France and its suburbs. The line crosses the region from east to west, with all t ...
was being extended west of Paris onto tracks that were part of the existing
SNCF
The Société nationale des chemins de fer français (; abbreviated as SNCF ; French for "National society of French railroads") is France's national state-owned railway company. Founded in 1938, it operates the country's national rail traffi ...
network, with the Cergy branch opening in 1988 and the Poissy branch opening in 1989. These tracks were powered with
25kV AC traction power, not the
1.5 kV DC
This is a list of the power supply systems that are, or have been, used for tramway and railway electrification systems.
Note that the voltages are nominal and vary depending on load and distance from the substation.
Many modern trams and trains ...
used on
RATP's existing tracks.
This required new equipment, capable of operating on both networks (interconnecting). The existing
MS 61
The MS 61 (French: ''Matériel Suburbain de 1961'', English: ''Suburban rolling stock of 1961'') was an electric multiple unit trainset that was operated on line A and line B of the Réseau Express Régional (RER), a hybrid suburban commut ...
equipment was only capable of operating under 1.5kV DC and the RER A rolling stock fleet was in need of expansion after earlier extensions to the east of Paris.
To meet the need, in 1984 RATP purchased the MI 84 (French: ''Matériel d'Interconnexion de 1984'', English: ''interconnection rolling stock of 1984'') based on the earlier
MI 79
The MI 79 (French: ''Matériel d'Interconnexion de 1979'', English: ''interconnection rolling stock of 1979''), also known as the Class Z 8100 is a Multi-system (rail), dual-voltage electric multiple unit trainset that is operated on RER B, line ...
which was still in production.
The MI 84 would prove to be somewhat problematic on the RER A line. Two trainsets coupled together were only long, compared to three MS 61 trainsets which could be up to long. As the only equipment capable of serving the Cergy and Poissy branches, the MI 84 trainsets also received intense usage.
Between 1990 and 2005, ridership on the RER A was growing at an average of 9% per year, leaving RATP looking for ways to increase capacity on the line. In 1997, the agency introduced the
MI 2N ''Altéo'', a double-deck, dual-voltage trainset. The double-deck trains proved so successful and popular, all remaining single-level trainsets were replaced with another order of double-deckers, the
MI 09
The MI 09 (French: ''Matériel d'Interconnexion de 2009'', English: ''interconnection rolling stock of 2009'') is a double-deck, dual-voltage electric multiple unit trainset that is operated on line A of the Réseau Express Régional (RER), a ...
.
After the purchase of the double-deck equipment, the MI 84 trainsets were reassigned to the
RER B
RER B is one of the five lines in the Réseau Express Régional (English: Regional Express Network), a hybrid commuter rail and rapid transit system serving Paris, France and its Île-de-France suburbs. The RER B line crosses the region from no ...
which needed additional equipment to handle increasing passenger traffic.
As of 2020, all of the MI 84 trainsets are on the RER B, stored in good condition at Torcy or scrapped.
Design
![Interieur MI84](https://upload.wikimedia.org/wikipedia/commons/d/d2/Interieur_MI84.jpg)
The original interior of the MI 84 is similar to that of the original MI 79, with some differences.
Because the RER B serves
Charles de Gaulle Airport
Paris Charles de Gaulle Airport (french: Aéroport de Paris-Charles-de-Gaulle, ), also known as Roissy Airport or simply Paris CDG, is the principal airport serving the French capital, Paris ( and its metropolitan area), and the largest intern ...
, the MI 79 trains were equipped with overhead luggage racks. Because the RER A mostly serves suburban commuters, the luggage racks were eliminated on the MI 84, which also allowed heating and ventilation ducts to be moved to the ceiling (a less expensive design) and different lighting to be installed.
To accommodate the heavier passenger traffic on the RER A, the MI 84 had about 15% fewer seats, allowing more standing passengers. MI 84 trains are also equipped with anti-laceration seats which are more durable, but less comfortable than the thick leatherette seats of the MI 79.
By choosing to base the design of the MI 84 on the earlier MI 79, RATP enjoyed a lower initial purchase cost and by sharing many parts between the two models long-term maintenance costs were reduced. However, RATP did opt to make some mechanical changes to the MI 84 to take advantage of recent technological progress.
The MI 84 uses microprocessors to control the propulsion systems (compared to the analog controls on the MI 79), simpler traction motors (the same as the SNCF Z2N trains) that were capable of "
self-excitation
An electric generator or electric motor consists of a rotor spinning in a magnetic field. The magnetic field may be produced by permanent magnets or by field coils. In the case of a machine with field coils, a current must flow in the coils to ge ...
" and adds a coolant system to remove heat from the chopper thyristors (the MI 79 used air cooling). Despite the changes, the MI 84 is still capable of being
coupled and operated together with a MI 79 trainset.
Technical details
The MI 84 takes advantage of the technological advancement that had occurred since the construction of the MI 79 series. However, the MI 84 had to keep the same basic mechanical and electrical structure so they could be coupled to the MI 79.
Both the MI 84 and MI 79 use the same EHO 3262 A direct current (DC) motors. Two are installed per trainset and each develops .
[http://fbrisou.free.fr/RAIL21/fichez8100 ]
The control system is the one that has benefited the most from the improvements. The MI 79 used analog TCO air-cooled
chopper with
thyristor
A thyristor () is a solid-state semiconductor device with four layers of alternating P- and N-type materials used for high-power applications. It acts exclusively as a bistable switch (or a latch), conducting when the gate receives a current ...
s. The MI 84 uses a digitally controlled, liquid-cooled chopper with thyristors. Early models were built by TCO and later units were built by
Alstom
Alstom SA is a French multinational rolling stock manufacturer operating worldwide in rail transport markets, active in the fields of passenger transportation, signalling, and locomotives, with products including the AGV, TGV, Eurostar, Avelia ...
and use four quadrant chopper with GTO components .
There is a
self-excitation
An electric generator or electric motor consists of a rotor spinning in a magnetic field. The magnetic field may be produced by permanent magnets or by field coils. In the case of a machine with field coils, a current must flow in the coils to ge ...
of the traction motors in the energy recovery phase. Simplification and reduction of the power of the static converter of the train (from 95 kVA to 30 kVA), made possible in particular by the “self-excitation” of the traction motors in the recovery phase.
The H-shape frame bogies with end sill are the same as the MI 79, manufactured by ANF.
Transmission is via a hollow shaft around the axle as MI 79.
[http://fbrisou.free.fr/RAIL21/fichez8100 ]
The braking system is also identical with
disc,
dynamic
Dynamics (from Greek δυναμικός ''dynamikos'' "powerful", from δύναμις ''dynamis'' "power") or dynamic may refer to:
Physics and engineering
* Dynamics (mechanics)
** Aerodynamics, the study of the motion of air
** Analytical dynam ...
, and
eddy current
Eddy currents (also called Foucault's currents) are loops of electrical current induced within conductors by a changing magnetic field in the conductor according to Faraday's law of induction or by the relative motion of a conductor in a mag ...
brakes. Although, unlike the MI 79, the dynamic brakes are not
rheostatic.
Formations
As of 25 December 2021, 41 MI 84 trainsets were based at the Massy RATP depot. Additionally, some MI 84 trainsets are stored in good condition at the Torcy RATP depot on the RER A Line.
As shown below, the trainsets are formed with two motored cars and three non-powered (trailer) cars (2M2T).
* < or > show a pantograph. Cars 2 and 3 were each equipped with one type AM 62 BU pantograph.
* Car 2 was formerly a mixed 1st class and 2nd class car.
Refurbishment
The introduction of the
MI 09
The MI 09 (French: ''Matériel d'Interconnexion de 2009'', English: ''interconnection rolling stock of 2009'') is a double-deck, dual-voltage electric multiple unit trainset that is operated on line A of the Réseau Express Régional (RER), a ...
series of double-decker trainsets on the RER A allowed RATP to shift the MI 84 trains to the RER B by 24 February 2017. By this time, the MI 84 trains were worn out after two decades of intensive use on the RER A and needed a refurbishment.
In 2018,
Île-de-France Mobilités
Île-de-France Mobilités (ÎDF Mobilités), formerly ''STIF'', is the brand name of the ''Syndicat des transports d'Île-de-France'', the organisation authority that controls and coordinates the different transport companies operating in the ...
approved a €100 million contract with Alstom (the original builder of the trains) to refurbish 33 of the MI 84 trains. The refurbishment will add a
cooled air ventilation system, security cameras and LED lighting. New seats and flooring will also be added that will create an interior that appears similar to the refurbished MI 79 trains. RATP believes the refurbishment will make the MI 84 trains more reliable and will enable more regular service on the RER B.
The first refurbished train was placed into service on 7 October 2020 and Alstom plans to finish the refurbishment of all 33 trains by 2022.
Gallery
References
External links
{{Paris Metro/RS
Electric multiple units of France
Réseau Express Régional multiple units
SNCF multiple units
Train-related introductions in 1985