  Classical methods of differential geometry are used to construct equations of
motion for particles in quantum, electrodynamic and gravitational fields. For a
five dimensional geometrical system, the equivalence principle can be extended.
Local transformations generate the effects of electromagnetic and quantum
fields. A combination of five dimensional coordinate transformations and
internal conformal transformations leads to a quantum Kaluza-Klein metric. The
theories of Weyl and Kaluza can be interrelated when charged particle quantum
mechanics is included. Measurements of trajectories are made relative to an
observers' space that is defined by the motion of neutral particles. It is
shown that a preferred set of null geodesics describe valid classical and
quantum trajectories. These are tangent to the probability density four vector.
This construction establishes a generally covariant basis for geodesic motion
of quantum states.
