  All equivalence classes for electromagnetic potentials and space-time metrics
of Stackel spaces, provided that Hamilton-Jacobi equation and Klein-Gordon-Fock
equation for a charged test particle can be integrated by the method of
complete separation of variables are found. The separation is carried out using
the complete sets of mutually-commuting integrals of motion of type (1.1).
Whereby in a privileged coordinate system the given equations turn into
parabolic type equations. Hence, these metrics can be used as models for
describing plane gravitational waves.
