The SNCF Class Z 26500 and Z 24500 are a series of electric multiple unit (EMU) trains with bi-level carriages, derived from the Coradia Duplex type of Alstom.

Indeed, the varied requirements of regions and travellers required the development of a flexible train able to be more accessible to people with reduced mobility (PRM), reach 160 km/h (100 mph) (compared to 140 km/h (90 mph) for TER 2N), cross the borders in the North-East 25 kV AC region, and be more comfortable for routes up to 2 h 30 min.

It also needed to offer a variety of passenger areas and be subject to enhanced passive safety, meeting the latest regulations in force.

Alstom used its Coradia platform to offer new equipment, a full-scale model of which was assembled in 2002 and then presented to the public and communities to validate the choices of interior fittings.

In addition, the Luxembourg railways (CFL) acquired twelve 3-car trainsets, intended to be pooled with those of the neighboring Lorraine region.