ABSTRACT
Active suspensions utilise control systems technology in order to provide a step change in performance of the dynamic characteristics of railway suspensions, and this chapter is an important complement to other chapters in the handbook, which are focussed upon essentially ‘passive’ suspensions. It describes the three main types: tilting trains which represent an existing, widely utilised active suspension technology that enables higher speed through curves; active secondary suspensions which are aimed towards enhanced ride quality; and active control of the running gear (active primary suspensions), which offers substantial improvements in the trade-off between dynamic stability and curving performance. Principles, configurations and design issues for each of these types are described, and some examples are included, both to illustrate some key aspects and to reveal the current state of the art.
