Catalyzes the stereospecific reduction of the C-4 keto group of dTDP-4-dehydro-6-deoxy-D-glucose, leading to dTDP-D-fucopyranose. This is a step in the biosynthesis of D-fucofuranose, a component of E.coli O52 O antigen. Is more efficient using NADH than NADPH as cosubstrate. dTDP-alpha-D-fucose + NAD(+) = dTDP-4-dehydro-6-deoxy-alpha-D-glucose + H(+) + NADH dTDP-alpha-D-fucose + NADP(+) = dTDP-4-dehydro-6-deoxy-alpha-D-glucose + H(+) + NADPH Inhibited by Cu(2+), while other divalent cations such as Ca(2+), Co(2+), Fe(2+), Mn(2+) and Mg(2+) have no obvious effects on enzyme activity. kcat is 406 min(-1) for the reduction reaction with NADPH, and 1594 min(-1) for that with NADH. Optimum temperature is 15-37 degrees Celsius. Active over a broad range of temperatures, from 4 to 80 degrees Celsius. Bacterial outer membrane biogenesis; LPS O-antigen biosynthesis. Cells lacking this gene produce semirough (SR-type) LPS with only one O unit attached to the core-lipid A moiety while the wild-type strain produces normal LPS. Belongs to the NAD(P)-dependent epimerase/dehydratase family.