UIC comfort tests - VTI

The tilt compensation ratio indicates how large proportion of the lateralacceleration in the track plane is reduced (compensated) and perceived by thepassengers:k c = 100 ⋅ (1 – f r ) , if f r < 1. [%]Note: There is a difference between theoretical tilt compensation in the tilt controlsystem and the actual tilt compensation because of the roll-out in the suspensionsystem.Conclusion of this sectionThe lateral acceleration in the horizontal plane is the most important effect of theride in curved track, both in amplitude and duration. The effect of thatacceleration is balanced by the angular position of the track (cant) plus any extratilting of the coach.There is always an angle where the resulting lateral force perceived by thepassenger is zero.In conclusion, for a coach of zero length it is in theory possible to reduce thelateral acceleration to zero for each point of the track for a given speed, but thevertical acceleration and the roll angle will increase.Therefore, in the curve transition the local radius and local cant angle of thetrack must follow some rules. In general, the angle of the track relative to thehorizontal plane changes in a linear way from zero to the value used in the circularcurve.For a number of reasons full compensation is not wanted.VTI notat 56A-2003 25