Motion rotating seat particularly for a railway vehicle

A seat comprising an upper part (14) for accommodating at least one occupant, carried by a lower part forming an underframe (16), and means (28) for turning the upper part (14) round to face the other way, and back again,

• wherein the turning-round means (28) comprise:
• a carriage (30), carried by the upper part (14), and a straight guide (32) carried by the underframe, the carriage being movable with respect to the underframe in substantially horizontal translation in the straight guide, and the carriage being movable in rotation about a substantially vertical geometrical axis (Z) of rotation fixed with respect to the carriage when the carriage moves in translation in the straight guide,
• means (52) for driving the carriage (30) in translation in the straight guide, and
• meshing means (54) which comprise a first toothed part, carried by the upper part, and a second toothed part carried by the lower part, the first toothed part and the second toothed part meshing when the upper part moves in translation in the straight guide so as to impart a rotational movement of the carriage and of the upper part around the geometrical axis of rotation.