An adapter rail system for mounting objects to a floor rail in a vehicle includes an elongate adapter rail element, an arresting element and a movement rail element. The adapter rail element has a surface contour having regularly consecutively arranged neckings and widenings, which surface contour corresponds to an opening contour of a floor rail, which includes regularly consecutively arranged grid openings, which are penetrated by a slit. The adapter rail element has protrusions extending perpendicular to the plane spanned by the surface contour and are each arranged in the region of a necking. The arresting element has a surface contour corresponding to the opening contour of at least one grid opening. The arresting element is dimensioned to be flush between two adjacent protrusions of the adapter rail element onto the adapter rail element. The movement rail element is connectable with the protrusions of the adapter rail element.