  We study the low-temperature transport of a doped two-chain ladder system of
interacting fermions in the presence of a barrier or of a low concentration of
impurities. Above a certain value of the interaction, the conductance is
suppressed, like for a single chain, despite the presence of dominant
superconducting correlations. There is, however, a region of repulsive
interaction where perfect transmission across the barrier occurs unlike the
single-chain case. We provide a possible explanation for the temperature
maximum of the resistivity in the normal state of \srca.
