5. To reduce size, mass, and cost a traction motor is used which runs at a speed considerably higher than that of the axle that it drives. A speed reduction gearhox is used between the motor armature shaft and the axle. To reduce the unsprung mass on the axles and hence the amount of track damage, the two traction motors are mounted on the bogie frame and thus fully sprung by the primary suspension. Each gearbox is mounted on the axle by two taper roller bearings and the pinion is carried on its own shaft in the upper half of the gearbox by two additional taper roller bearings. The gear wheel is mounted directly on the axle. The drive from the motor armature is to a short cardan shaft through a flexible coupling. The cardan shaft passes through the hollow centre of the pinion shaft and is connected to it at the far end by a second flexible coupling. A torque reaction link with bonded rubber bushes couples the gearhox to the bogie frame. The gearhox is overall about 110Ox600x3M) mm.
