A floor structure of a rail vehicle car body having a left and a right sidewalls, the floor structure comprising: a left longitudinal beam and a right longitudinal beam, the left and the right longitudinal beams extending longitudinally along the respective left and right sidewalls of the car body; a plurality of transverse structural members, each transverse structural member being directly and permanently fixed at its one end to the left longitudinal beam and at its other end to the right longitudinal beam, the transverse structural members extending in a transverse direction of the car body, each transverse structural member being placed at a predetermined longitudinal distance from each other; and a floor panel, characterized in that the floor structure comprises a plurality of fasteners, the plurality of fasteners being of the non-permanent, reclosable, pressure-interlocking type, each fastener having a first and a second interlocking halves (32, 34), each transverse structural member being provided on an operatively mating surface with one of the first interlocking halves of the plurality of fasteners at a predetermined transversal distance from the left longitudinal beam, the floor panel being provided on its underside with the second interconnecting halves of the plurality of fasteners, the second interlocking halves being longitudinally installed at the predetermined longitudinal distance from each other and transversely installed at the predetermined traversal distance from the left longitudinal beam so as to correspond to a position within the rail car of their respective first interlocking half of the plurality of fasteners, the floor panel being removably and directly attached atop the plurality of transverse structural members through interlocking the corresponding first and second interlocking halves (32, 34) of each one of the plurality of fasteners. a left longitudinal beam and a right longitudinal beam, the left and the right longitudinal beams extending longitudinally along the respective left and right sidewalls of the car body; a plurality of transverse structural members, each transverse structural member being directly and permanently fixed at its one end to the left longitudinal beam and at its other end to the right longitudinal beam, the transverse structural members extending in a transverse direction of the car body, each transverse structural member being placed at a predetermined longitudinal distance from each other; and a floor panel, characterized in that the floor structure comprises a plurality of fasteners, the plurality of fasteners being of the non-permanent, reclosable, pressure-interlocking type, each fastener having a first and a second interlocking halves (32, 34), each transverse structural member being provided on an operatively mating surface with one of the first interlocking halves of the plurality of fasteners at a predetermined transversal distance from the left longitudinal beam, the floor panel being provided on its underside with the second interconnecting halves of the plurality of fasteners, the second interlocking halves being longitudinally installed at the predetermined longitudinal distance from each other and transversely installed at the predetermined traversal distance from the left longitudinal beam so as to correspond to a position within the rail car of their respective first interlocking half of the plurality of fasteners, the floor panel being removably and directly attached atop the plurality of transverse structural members through interlocking the corresponding first and second interlocking halves (32, 34) of each one of the plurality of fasteners.