They are derived from the two-car X 4630 DMU with which they share the same Saurer 330 kW (440 hp) engines as well as their hydraulic gear box.

The railcars possessed more power than the other Caravelles as they are formed of two motor coaches and one intermediate trailer, this authorised them to run at a top speed of 140 km/h (87 mph).

Aesthetics are different from the other Caravelles as the painting scheme chosen is English blue, white and grey.

Their superior power led to their allocation to passenger service duties on steep gradient routes in the Southern Alps.

The 10 trains belonging to Haute-Normandie received the TER as well as a modernised cab, identical to that of the X 4630 renovated DMUs.