  In this manuscript we use the dynamical system approach to study the linear
dynamics of a normal DGP brane-world model with a tachyon field as the dark
energy component. Our focus is on a Gaussian tachyonic potential in which the
parameter $\lambda=-V_\phi/V^{3/2}$, goes to infinity. One of the most
important results of this study is that we find critical submanifolds which
indicate the effect of extra dimension.
