Optimization of the specifications of carbody, truck and their connecting elements to improve the riding comfort of railway vehicles.

It is important to optimize the combination of specification parameters of carbody, truck, and their connecting elements to reduce bending vibration of railway carbody and to improve riding comfort. This paper presents the optimization of the specification parameters using the genetic algorithm (GA). The riding comfort level (LT) at the center of carbody is used as the objective function and the specific parameters are taken as design variables. A beam model, in which the carbody is treated as an elastically supported beam, is used to calculate LT. The effects of carbody and truck connecting elements, such as traction links and anti-yaw dampers, are taken into account in the calculation model. It is shown through numerical calculation that bending vibration can greatly be reduced and LT is also improved as a result of the optimization method presented in the paper. A running test for a real Shinkansen train is also carried out to confirm the effectiveness of the method. It is found that the bending vibration is reduced to a large extent and LT can be improved by 2 dB or over, in the case, where the specifications of traction links and anti-yaw dampers are modified based on the result of GA optimization.