The bogie of variable rail gauge comprises two lateral carrier mountings (1;2) with two wheels (1′, 1″, 2′, 2″) independent of each others, which lean one against the other, forming between them an articulation (3) allowing a variation of the rail bogie in sliding between the traverses forming part of the two lateral carrier mountings (1;2), entirely, allowing anytime a relative rotation or tipping, respectively, between the traverses (2;3) in the vertical planes of the wheels.