Modelling of aerodynamic force acting on high speed train in tunnel and a measure to improve the riding comfort utilising restriction between cars

For a train running at high speeds in a tunnel, the car body vibration considerably increases due to the aerodynamic force generated around the car body, thereby deteriorating riding comfort. To improve riding comfort of a train running at high speeds in a tunnel, the effects of stiffness and damping between adjoining cars are examined. In case the restriction between cars is too large, the curving performance may deteriorate around sharp curves. In this paper, analytical models of the aerodynamic force and a train are developed, and the riding comfort at high speed in a tunnel and the curving performance around a sharp curve are simulated. As a result, a solution, which improves the riding comfort at high speeds without increasing the wheel lateral force around sharp curves, is found by increasing inter-vehicle damping in the longitudinal and lateral directions.