  Penrose limits are considered in space-times admitting two abelian,
space-like Killing vectors in vacuum as well as in the presence of an
electromagnetic field. This type of space-times describe inhomogeneous
cosmologies as well as colliding plane gravitational and electromagnetic waves.
Following the work of Tod [1] the conditions for diagonal Penrose limits are
investigated in these backgrounds. The twistor equation is considered in these
space-times and solutions given in the Penrose limit.
