By means of the invention there is provided a frame for rail vehicles comprising at least four rail wheels (1a, 1b) arranged thereon on at least two axles (2, 3) each having a variable track ) and a stretching device that stretches the rail wheels (1a, 1b) of each axle (2, 3) in the direction of variable track width; it also includes The modified and improved guides of the variable track, as guide plates not disclosed in the prior art and used here, also work reliably in the region of damaged rails and small bending radii. In the rail vehicle according to the invention, at least two axles (2, 3) variable in their respective wheelbases are connected by connecting means (8a, 8b) in such a way that such axles (2, 3) Has a minimum track that can also be used to preset other axes (2, 3).