Inside Frame Bogies & AIR Wheelset: A Winning Marriage

Inboard bearings bogies are spreading rapidly in the last years. Their superior characteristics in terms of lower total mass, unsprung mass and moments of inertia give the vehicles an excellent curving behaviour and a very high track friendliness. They also open new possibility to overcome some maintenance issues of conventional wheelsets. In fact, as the wheels are easily accessible, a specific wheelset arrangement, named AIR wheelset, was recently developed and patented for these bogie frames. The paper focuses on the introduction of the AIR wheelset on inboard bearings bogie frame design. The paper will consider both driving and trailing wheelsets, with and without torque limiter, in the same range of application of some of the existing bogie frames produced by worldwide rolling stock suppliers. With some detailed examples, it will be shown that the modifications required are very limited and that therefore the application of AIR Wheelset is relatively straightforward and may have a deep impact on reliability, availability and life cycle cost of the bogie. Some parts of the wheelset become in fact part of the bogie frame and the maintenance sequence is dramatically simplified generating considerable savings.