A railway direct-current system according to the present invention is provided with: a feeding line that is connected to a plurality of electric power substations arranged along a railway; and a trolley line that is connected to the feeding line via feeding branch lines at an arbitrarily defined interval, wherein a superconductive feeding cable is connected to somewhere midway in each of railroad lines extending from the substations to the trolley line via the feeding lines, so as to be parallel with the railroad line.