INFLUENCE OF DIFFERENT CONDITIONS OF TILT COMPENSATION ON MOTION AND MOTION-RELATED DISCOMFORT IN HIGH-SPEED TRAINS

Train speed may be increased by constructing new railways with improve d curve geometry or by using tilting trains. The tilting system compen sates the lateral acceleration felt by the passengers in curves by til ting the car body, thus allowing trains to run 25-30 % faster on exist ing curved tracks with maintained good ride comfort. Although motion s ickness in tilting trains seems to be a small problem for most passeng ers it can be a problem to those prone to nausea. To investigate the i ncidence of motion related discomfort and how different tilt compensat ion strategies influence the occurrence of such discomfort, a full-sca le test ride was conducted on a curved track with a tilting train. Sev enty healthy volunteers were employed, selected for high subjective se nsitivity to nausea. Three conditions were tested using three differen t cars under three days. The test ride lasted about 3 hours. Four time s per test ride the subjects answered a questionnaire concerning veget ative symptoms, fatigue, sleepiness and nausea. The test persons' over all estimation of average ride comfort was good in all conditions, how ever, some persons reported motion related discomfort due to motion si ckness. A 55% degree of tilt compensation of the lateral acceleration (in the track plane) instead of the normal 70%, reduced the number of test persons reporting dizziness and nausea by about 30 - 50%. Discomf ort correlates very poorly with a motion dose (time integrated) of ver tical acceleration but instead correlates better with a motion dose of roll angle acceleration.