Active components are starting to become accepted within railway vehicle suspension systems which have been exclusively mechanical since railways began in the 1800s. At the moment these are principally being applied in tilting trains, but opportunities which arise from applying control systems engineering to railway suspensions extend much further, and this is the first of two articles which explore such possibilities. Part 1 concentrates on control approaches which are mainly concerned with passenger comfort-active tilting technology which enables trains to go faster around curves without passengers experiencing the higher curving accelerations, and active secondary suspensions which also improve the essential ride quality on straight track.