... material: cast steel or cast iron 2. constitute: two wheels, one axle, four bearings, and other parts.3. ... , 900mm, and etc.5. the type of the wheels: hollow wheel sets and solid wheel sets.6.the ... diameter of the wheels: 300mm, 350mm, 400mm, 450mm7.the material of the ... mine car, mining car wheels, wheel pairs, wheel sets, U channel steel beam arch, mining light steel rails ...