The SNCF Class Z 22500, also known as the MI 2N "Eole" or MI 2N (French: Matériel d'Interconnexion à 2 Niveaux, Est Ouest Liaison Express, English: two-level interconnection rolling stock for the east west express link) is a double-deck, dual-voltage electric multiple unit trainset that is operated on line E of the Réseau Express Régional (RER), a hybrid suburban commuter and rapid transit system serving Paris and its Île-de-France suburbs.
The 53 five-car trains were built by a consortium of French manufacturer Alstom (then known as GEC Alsthom) and Canadian conglomerate Bombardier.
To address this issue, several projects were launched: the SNCF started construction of the Est Ouest Liaison Express (EOLE; English: east west express link) which would later be known as the RER E line, while the RATP started construction of the Paris Métro Line 14, both of which would both parallel the RER A in central Paris.
In November 1992, they placed an order for 17 MI 2N trainsets from a consortium of French manufacturer Alstom (at the time known as GEC Alsthom) and Canadian conglomerate Bombardier.
The two trains look very similar from the outside, but the Class Z 22500 would only have two motors (the Altéo would feature three motors per trainset for faster acceleration) and would eliminate the stairs to the upper deck to the center vestibule adding 22 additional seats per train (the Altéo kept the stairs to speed the movement of passengers at stations).
Unlike the MI 2N Altéo of the RATP, the Z 22500 are not equipped with refrigerated ventilation, nor with the driving assistance system, operation and maintenance (SACEM) used on the RER A.
For example, train 10E is composed as follows: ZRBxe221519 - ZBxe22519 - ZRBe222519 - ZABe22520 - ZRBxe221520 The ZRBxe are equipped with a pantograph and a driver's cab but are not motorized, which sometimes confuses people.
They are also equipped with passive safety devices designed for new generations of TGV (energy absorbers, anti-overlap system between each car) intended to guarantee the safety of passengers and the driver, in the event of a collision; they also have a central brush for the "tunnel recognition" of the E line.