Test particle motion in a gravitational plane wave collision background

Test particle geodesic motion is analysed in detail for the background spacetimes of the degenerate Ferrari-Ibanez colliding gravitational wave solutions. Killing vectors have been used to reduce the equations of motion to a first-order system of differential equations which have been integrated numerically. The associated constants of motion have also been used to match the geodesics as they cross over the boundary between the single plane wave and interaction zones.