An axle box for a railway vehicle bogie comprises a rolling bearing having an outer ring element, an inner ring element, rolling elements mounted there between, and a seal element, the inner ring element being adapted to be secured by screw bolts to an axial end of bogie axle. The axle box comprises an end cap comprising a flange with an inner face and an outer face, an annular first radial surface portion of the inner face being so defined that it is able to lean against an axial end of the inner bearing ring element of the rolling bearing. The flange comprises a central part traversed by screw bores. The flange comprises a first inner axial ridge running alongside the outer circumference of the cap, and extending axially towards the rolling bearing all around the flange, further than the first radial surface portion.