ABSTRACT
Every rail vehicle (passenger or freight) requires a set of parts and devices for its movement: wheels, axles, bogies, springs, couplings and buffers.
19.2.1. Geometrical characteristics and materials
On standard gauge tracks, the wheel diameter of the hauled rolling stock ranges from 0.84m to O.92m. As the continuing tendency is to increase wheel load, one would expect wheel diameter to increase also. This, however, is not feasible beyond current wheel diameters, because larger wheels would on the one hand increase weight and therefore manufacturing and operating costs, and on the other hand result in a greater vehicle floor height from track level. This would be detrimental to both the stability and the space available in the vehicle, since the loading gauge of the track (i.e., the free space around the rolling stock) is fixed and cannot be changed.
