  A method is given to generate the non-linear interaction (collision) of
linearly polarized gravity coupled torsion waves in a non-metric theory.
Explicit examples are given in which strong mutual focussing of gravitational
waves containing impulsive and shock components coupled with torsion waves does
not result in a curvature singularity. However, the collision of purely torsion
waves displays a curvature singularity in the region of interaction.
