Railway brake disc

A brake disc comprising:

• a cylindrical hub having a rotary axis and having an inner cylindrical surface defined by the rotary axis, a given diameter, and a given axial length, said hub having a radial thickness defined by the inner cylindrical surface and an outer generally cylindrical surface;
• two friction rings coaxial with the hub axis having parallel opposite-facing braking surfaces, said friction rings having an axial thickness defined by the braking surfaces and interior surfaces, there being central openings in the friction rings extending from the hub axis and having a diameter greater than the diameter of the outer generally cylindrical surface of the hub, said friction rings having generally circular outer edges;
• a plurality of pairs of spoke flanges extending between the outer generally cylindrical surface of the hub and said friction rings, said spoke flanges having axially extending widths defined by inner and outer faces, each spoke flange in a pair of spoke flanges being axially spaced from the other and each spoke flange connected with a different friction ring, the spoke flanges having generally radial edges such that edges of the central openings in the friction rings and edges of the spoke flanges define generally trapezoidal openings between the hub and the friction rings;
• and
• a plurality of radial spoke webs having a thickness defined by generally flat parallel faces, each spoke web extending between and joining the hub and both friction rings such that a cross section of associated flange pairs and webs taken parallel to the hub axis has an I-beam shape.