The present invention relates to an operating and locking mechanism for diamond crossings of central rail-guided vehicles, comprising: a sliding plate (2A) fixed to a fixed part (2) of the diamond crossing forming a channel in its central area in the direction of the X axis, a guide block (10) fixed to the sliding plate (2A) comprising four guide grooves (10A, 10B, 10C, 10D) in the form of circular sectors located on the main plane of the guide block (10), the geometric center of which coincides with a theoretical pivoting point (17) of a moving panel (6) of the diamond crossing, where the sliding plate (2A) and the guide block (10) form a rectangular section groove (2F) the axis of which is parallel to the direction of the X axis, four shafts (12A, 12B, 13A, 13B) fixed to the moving panel (6) symmetrically with respect to a guide rail (7) of said moving panel (6) and perpendicular to the main plane of the moving panel (6), comprising respective rollers (12E, 12F, 13E, 13F) that can be moved and rolled respectively within the guide grooves (10A, 10B, 10C, 10D), and a cam plate (14) sliding in the longitudinal direction within the groove (2F) formed by the sliding plate (2A) and the guide block (10).