A guiding and support system (8; 80) for a leaf of a platform screen door, the leaf being able to be moved in relation to a fixed panel by a horizontal translational movement (D11, D12) in a plane of the leaf between open and closed positions in which the leaf at least partly frees or blocks an opening adjacent to the fixed panel, comprising: - a rail (11, 12; 1100) configured to be fixed to the leaf and extending in a direction of the horizontal translational movement, - a rail support comprising a plate forming a base that makes it possible to fix the rail support onto the platform edge coping and comprising a first post fixed onto the plate and extending by protruding therefrom vertically and a second post fixed onto the plate, at a distance from the first post, and extending by protruding therefrom vertically, - a first set of rollers (211, 212; 2210; 2114) cooperating with the rail to guide it and support it in the horizontal translational movement, each roller of the set of rollers comprising an axis of rotation at right angles to the plane of the leaf, said first set of rollers consists: - of a main roller in contact with a bottom bearing surface of the rail, said main roller being mounted free to rotate on one side of the first post, - of first and second secondary rollers offset relative to one another in at least one vertical direction and in contact respectively with the bottom bearing surface of the rail and a top bearing surface of the rail, the first and second secondary rollers being positioned at a distance from the main roller in the direction of the horizontal translational movement and in the direction of a transition from the closed position to the open position, said first and second secondary rollers (211, 212) being mounted free to rotate on a side of the second post, the main roller comprising two identical rollers (2211, 2212) positioned one behind the other in the direction of the horizontal translation movement, said two rollers (2211, 2212) being mounted, at least rotationally mobile about their own axis, on a link plate, said link plate being itself mounted to be rotationally mobile on the first post. - a rail (11, 12; 1100) configured to be fixed to the leaf and extending in a direction of the horizontal translational movement, - a rail support comprising a plate forming a base that makes it possible to fix the rail support onto the platform edge coping and comprising a first post fixed onto the plate and extending by protruding therefrom vertically and a second post fixed onto the plate, at a distance from the first post, and extending by protruding therefrom vertically, - a first set of rollers (211, 212; 2210; 2114) cooperating with the rail to guide it and support it in the horizontal translational movement, each roller of the set of rollers comprising an axis of rotation at right angles to the plane of the leaf, said first set of rollers consists: - a first set of rollers (211, 212; 2210; 2114) cooperating with the rail to guide it and support it in the horizontal translational movement, each roller of the set of rollers comprising an axis of rotation at right angles to the plane of the leaf, said first set of rollers consists: - of a main roller in contact with a bottom bearing surface of the rail, said main roller being mounted free to rotate on one side of the first post, - of first and second secondary rollers offset relative to one another in at least one vertical direction and in contact respectively with the bottom bearing surface of the rail and a top bearing surface of the rail, the first and second secondary rollers being positioned at a distance from the main roller in the direction of the horizontal translational movement and in the direction of a transition from the closed position to the open position, said first and second secondary rollers (211, 212) being mounted free to rotate on a side of the second post, the main roller comprising two identical rollers (2211, 2212) positioned one behind the other in the direction of the horizontal translation movement, said two rollers (2211, 2212) being mounted, at least rotationally mobile about their own axis, on a link plate, said link plate being itself mounted to be rotationally mobile on the first post.