  A recently introduced approach for the dynamical analysis and quantization of
field theoretical models with second class constraints is ilustrated applied to
linearized gravity in 3-D. The canonical structure of two different models of
linerized gravity in 3-D, the intermediate and the self dual models, is
discussed in detail. It is shown that the first order self dual model whose
constraints are all second class may be regarded as a gauge fixed version of
the second order gauge invariant intermediate model. In particular it is shown
how to construct the gauge invariant hamiltonian of the intermediate model
starting from the one of the self dual model. The relation with the t
opologically massive linearized gravity is also discussed.
