This is an animation showing how a PWay Track Horizontal Alignment Virtual Transition is defined by the trajectory of the vehicle centre, when is passing over a railway track section with a sudden change in curvature:

Virtual Transition animation – the vehicle centre is describing a curve (red) as the vehicle is passing over the area of a sudden change in curvature for the horizontal alignment.

The nature of this curve is presented in this post: THE VIRTUAL TRANSITION CURVATURE VARIATION.

More details about this principle and an alternative approach used in Europe for designing a sudden change in curvature is presented in my article “A different view on Virtual Transition. When is a transition curve not needed?”, published in the PWI Journal – October 2015:

(click on the image to read the online version of the article on Academia.edu)