Trains with a view to sickness

We report the findings of a panEuropean study on the factors which provoke motion sickness on tilting trains. The findings also highlight tactics passengers may use to ameliorate their malaise. Some readers may recall that the tilting train programme under development in the UK some 30 years ago was halted because of a combination of technical problems and reports of high levels of motion sickness which were not subject to a scientific study at that time. Currently, there is limited use of tilting trains in France and Italy but their imminent widespread deployment throughout Europe, scheduled for 2002 in the UK, threatens the situation that unacceptable numbers of passengers may become ill. Whereas passengers are rarely motion sick on conventional trains [1], it is estimated that between 5% and 30% may become sick on tilting trains [2]. The symptoms develop specifically on winding tracks when the compensatory suspension maintains the coaches inertially upright (Figure 1a). Our study investigated features of tilting trains that provoke motion sickness and identified how passengers may protect themselves. The particular aspects of train motion selected for study were suggested from established features of motion sickness which suggested that provocative situations may develop when the coach tilts inwards on curves to align with the inertial vertical ‘gi’ (Figure 1a). Firstly there is a provocative conflict [3] that the passenger feels upright whereas the external scenery appears to tilt; a phenomenon known to be nauseogenic. Secondly, as in an aeroplane during banking, when rounding bends the passenger feels only a variation of gi intensity, mixed