  We construct the second variation Lagrangian for Randall-Sundrum model with
two branes, study its gauge invariance, find the corresponding equations of
motion and decouple them. We also derive an effective Lagrangian for this model
in the unitary gauge, which describes a massless graviton, massive gravitons
and a massless scalar radion. It is shown that the mass spectra of these fields
and their couplings to the matter are different on different branes.
