Altéo

MI 2N "Altéo" train stopped at Nation station, showing the wide entry doors, level boarding and stairs to upper and lower decks

The Réseau Express Régional (RER) is a hybrid suburban commuter and rapid transit system serving Paris and its suburbs. The RER A line is, by far, the busiest in the system and is the busiest single rail line outside of East Asia, serving over 1.2 million passengers per day.[1][2]

The line started experiencing rapid growth in the 1980s, with traffic increasing by 9% per year on average. In an effort to relieve overcrowding on the line, the RATP began installing the SACEM electronic train control system (which enabled extremely short spacing between trains) and started looking at purchasing double-deck trains.

Double-deck trains, like the Z 2N series (Class Z 5600 and Class Z 8800) were already in use on suburban SNCF networks and could carry up to 2,600 people per train, compared to 1,887 people on the single-deck MS 61 trains that had been used on the RER A since it opened.

At about the same time, the RATP started construction of the Paris Métro Line 14 and SNCF started construction of the RER E line, which would both parallel the RER A in central Paris.

That left the RATP and the SNCF looking for new equipment for the RER A and E lines, so in 1989 they decided to team up and issue a call for tenders. In 1992, they placed an order for 17 MI 2N trainsets from a consortium of French manufacturer Alstom (at the time known as GEC Alstom) and Canadian conglomerate Bombardier. The MI 2N would be based on the design of SNCF's Class Z 20500 trains being built by the same consortium for RER C and RER D lines, but with modifications to make them better suited to the busy RER A line, most notably three wide doors on each side of the cars (the Z 2N only had two).[3]

The RATP trains for the RER A would be called the MI 2N "Altéo", and the SNCF for the RER E would be called the Class Z 22500, also known as the MI 2N "Eole" (EOLE was the name of the RER E during construction). The two trains look very similar from the outside, but the MI 2N "Altéo" trains for the RER A would feature three motors per trainset for faster acceleration (the SNCF trains would only have two motors) and stairs from the upper deck to the center vestibule (SNCF trains would eliminate the stairs in favor of having 22 additional seats per train).[3]

A pre-production train was delivered in 1996 for joint testing by both RATP and SNCF. The first order of 17 trainsets was delivered between 1997 and 1999 and the first train was put into service on 6 June 1997. RATP ordered a second option of 12 trainsets was delivered between 2001 and 2002 and a third option of 14 trainsets was delivered between 2003 and 2005.

The double-deck trains proved so successful and popular, operators of the RER A went on to purchase 140 MI 09 trainsets, an improved version of the MI 2N that would be built by the same Alstom-Bombardier consortium.[4]

Altéos are able to operate on two different types of electrical power: RATP's 1.5 kV DC network and SNCF's 25 kV AC network. The trains primarily operate using 1.5 kV DC, except when operating over the western A3 and A5 branches (between Houilles–Carrières-sur-Seine station and Cergy-le-Haut station or Poissy station).

Altéos made their commercial debut on 6 June 1997. 43 trainsets with a total of 215 cars were built for the RER A line.

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  MI 2N "Altéo" boarding passengers at Cergy–Saint-Christophe station
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  MI 2N "Altéo" interior, upper deck
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  MI 2N "Altéo" interior, lower deck
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  MI 2N "Altéo" interior, mid-deck showing the wide entry doors, and stairs to upper and lower decks
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  Operators compartment
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  MI 2N "Altéo" interior, mid-deck showing the SISVE lighted route map

• MI 2N page on Metro-pole.net (in French)

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