  In this paper we incorporate gauge fields into the tachyon field theory
models for unstable D-branes in bosonic and in Type II string theories. The
chosen couplings yield massless gauge fields and an infinite set of equally
spaced massive gauge fields on codimension one branes. A lack of a continuum
spectrum is taken as evidence that the stable tachyon vacuum does not support
conventional gauge excitations. For the bosonic string model we find two
possible solvable couplings, one closely related to Born-Infeld forms and the
other allowing a detailed comparison to the open string modes on bosonic
D-branes. We also show how to include fermions in the type II model. They
localize correctly on stable codimension one branes resulting in bose-fermi
degeneracy at the massless level. Finally, we establish the solvability of a
large class of models that include kinetic terms with more than two
derivatives.
