Abstract: This invention relates to a safety wheel, for a subway coach bogie, or the like, running on pneumatic tires, adapted to be interposed between a chassis of the bogie and a corresponding tire, said wheel presenting an outer peripheral zone having a braking portion as well as a guiding portion projecting radially outwardly from the braking portion, the hardness of the braking portion being much greater than the hardness of the guiding portion. This may be achieved for example by effecting a selective tempering of the braking portion by peripheral nozzles projecting a cooling liquid. This safety wheel is considerably longer lasting than those of the prior art.

Abstract: A railroad wheel revolving around an XX' axle perpendicular to a median plane P, of the type that includes a rim with a rolling surface and a flange, a hub, a plate a connecting area of the plate with the rim, a connecting area of the plate with the hub and with the plate section constructed along a meridian line AB extending between a point A located at the junction of the plate and the connecting area of the plate with the rim and a point B located at the junction of the plate and the connecting area of the plate with the hub, and characterized by the fact that the two points A and B are located on either side of the median plane P and are symmetrical to one another in relation to the intersection point I of the meridian line AB and the plane P, with point I an inflection point for the curve AB.

Abstract: A railroad wheel revolving around an XX' axle perpendicular to a median plane P, of the type that includes a rim with a rolling surface and a flange, a hub, a plate a connecting area of the plate with the rim, a connecting area of the plate with the hub and with the plate section constructed along a meridian line AB extending between a point A located at the junction of the plate and the connecting area of the plate with the rim and a point B located at the junction of the plate and the connecting area of the plate with the hub, and characterized by the fact that the two points A and B are located on either side of the median plane P and are symmetrical to one another in relation to the intersection point I of the meridian line AB and the plane P, with point I an inflection point for the curve AB.

Abstract: Polyblock railway wheel of the type comprising a rim (1), a center part (2) constituted by a hub (22) and a web (6), a damper (5) disposed between the center part (2) and the rim (1), at least one flange (3), and fasteners (7) for fixing the at least one flange (3). The rim (1) comprises in its inner part (9) two connection fillets (10,11) located on opposite sides of the plane of symmetry of the wheel and interconnected in their innermost part, by a generally flat annular strip (12). The damper (5) has a tulip-shaped section. It comprises two rings (19,20) each formed by a ring of elastic polymer material inserted between and bonded to an upper metal flank (31) and a lower metal flank (32); the upper metal flank (31) cooperating with the innermost part (9) of the rim (1), and the lower metal flank (32) cooperating with a flange (3,4).

Abstract: In order to obtain, in service, a reduced acoustic emission, the position of the true point of contact (P) of the wheel with the rail is determined, the distribution of the masses of the section of the rim and of the wheel center of the wheel is adjusted so that the point of contact (P), the center of inertia (G1) of the section of the rim and the center of inertia (G2) of the section of the wheel center are located on one and the same straight line (XX') perpendicular to the axis (YY') and the outline of the section of the wheel is adjusted so that the point (P) is a vibration node for the axial vibration modes of the rim. The invention applies particularly to wheels for high-speed trains.

Abstract: A method for ultrasonically inspecting the surface of a bore, particularly the bore of a railroad wheel axle, includes the step of generating a transverse ultrasonic wave from an emitter which interacts with the surface of the bore, and comparing the amplitude of the echoes obtained with values obtained from a calibration curve plotted for a bore having a standard defect which corresponds to the bore to be inspected so as to determine the existance of a defect when the amplitude of the echoes is greater than a specified fraction of the value indicated by the calibration curve. A corresponding device is provided for ultrasonically inspecting the surface of the bore of the railroad wheel axle.

Abstract: The device includes a stand, a rail for supporting the wheel fixed to a horizontal part of the stand, longitudinal guide members fixed to a vertical part of the stand and extending in a direction parallel to the rail, slideways fixed to the horizontal part of the stand and extending in a direction parallel to the rail, and a carriage movable along the slideways. The carriage carries a grinding device and a hardness measuring device. Means permit applying a force on the hardness measuring device. An ultrasonic inspection device carried by the carriage may also be provided.

Abstract: The wheel rests upon a rail. A chassis mounted on a lifting and supporting mechanism carries slides arranged on either side of the rail and parallel to the rail. Two carriages are mounted to move translationally on the slides. Grinding devices, an ultrasound checking device and two position detectors are mounted on the carriages to move translationally in a direction perpendicular to the slides. The propagation time for the ultrasound in the rim is measured in two perpendicular directions and the width of the rim is measured. The propagation speeds of the ultrasound are calculated and compared so as to determine the stressed state of the rim.