Tilting trains reduce the perceived lateral acceleration for the passengers by tilting the car-body to improve the ride comfort. However, some susceptible passengers may experience nausea. To study the influence from either lateral accelerations and/or simultaneous roll motions, a simulator study was undertaken. About 40 subjects were taking part in the study with seven different combinations of lateral accelerations and roll motions. The maximum horizontal acceleration achieved was about 1.1 m/s2. The roll motion used, compensated the lateral acceleration with 0, 56, 75 or 100 per cent. Lateral jerk and roll velocity were in the range of a normal train environment. Test ride took 31 min in a two-seated cabin. Subjects answered a questionnaire each 5 min on their degree of nausea, illness and comfort. Main evaluation variables were nausea ratings (NR) and illness ratings (IR). The subjects also estimated their ride comfort, ability to work/read. The condition with only roll motion had a very low effect on NR and IR. High NR and IR were recorded in the conditions with combined high horizontal accelerations and large roll motion. Large variations in NR and IR were found between gender and also according to self-estimated sensitivity to motion sickness. Increasing speed in curves with tilting trains may enhance the risk of discomfort and nausea in sensible persons. The results of this study agree with earlier train studies that a lower degree of compensation of the horizontal acceleration (i.e. less roll motion) will reduce the risk of nausea. (Author/publisher)
Abstract