Controlling the ride quality of the central portion of a high-speed railway vehicle

Active suspension applied to railway vehicles is an area which has received considerable attention over recent years. The limits of passive suspension performance have been reached, but there is a need to maintain ride quality with the ever-increasing emphasis on lighter vehicles and higher speeds. A number of experimental active suspensions have demonstrated benefits and several manufacturers are now offering vehicles fitted with either semi-active or active suspensions. The beneficial effect inter-vehicle dampers have on ride quality means that they are now commonplace in highspeed train design. The fusion of the two ideas of active suspension and inter-vehicle dampers has spawned the concept of 'active inter-vehicle' suspension. This paper addresses this concept and attempts to resolve a number of issues, most notably the question: how much they can improve ride quality?.