2. A lateral damper to prevent vehicle derailment during earthquakes

• The RTRI developed a lateral damper for vehicles to prevent derailment during earthquakes.
• It also performed an actual bogie vibration experiment and simulation, and confirmed that the developed damper increased the limit of amplitude for running safety by a maximum of 17%.

The RTRI developed a lateral damper to prevent derailment during earthquakes (hereinafter referred to as the “anti-earthquake damper”) which increases vehicle running safety during earthquakes. Its performance in testing with a single unit demonstrated no difference from that of ordinary dampers up to a piston speed of 200 mm/s in ordinary ranges of use, and it generated a large stable damping force at speeds higher than this (Fig. 1). To verify the improvement provided by the anti-earthquake damper on running stability in earthquake conditions, an actual bogie vibration test was performed (Fig. 2). Excitation while increasing the amplitude to represent the estimated waves of the 2004 Niigata Prefecture Chuetsu Earthquake confirmed that, with the anti-earthquake damper, the wheels did not leave the rail until the input amplitude was approximately 9% greater than the corresponding value for an ordinary damper. Moreover, the ordinary damper was damaged during excitation and lost its damping function, while no such problems were encountered when using the anti-earthquake damper.

When an actual vehicle was equipped with anti-earthquake dampers, it was confirmed through simulation that the amplitude limit for running safety (the maximum amplitude of displacement at which derailment does not occur during excitation with sinusoidal waves) increases by a factor of 1.08 on average, and by a factor of up to 1.17 for an excitation frequency of 0.3 to 3.0 Hz (Fig. 3).
A running test at speeds exceeding 300 km/h using actual vehicles equipped with anti-earthquake dampers confirmed that they offered the same level of normal functionality as ordinary dampers.

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  Fig. 1 Anti-earthquake damper performance
  
  
  Fig. 3 Limit of running safety for a Shinkansen vehicle equipped with anti-earthquake dampers
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  Fig. 2 Vibration experiment on an actual bogie