Abstract: Methods and apparatus enabling simultaneous electrolytic tinplating of bottom and top surfaces of continuous-strip flat-rolled steel substrate while moving in the direction of its length, are disclosed. Both surfaces are plated in a first cell of a multi-cell horizontally-oriented tinplating line. The stannous ion plating source and the source of electrical power, for each surface, differ. Tin pellets for an upper surface anode are confined in a solution-permeable material confined, within an electrically-conductive lining. Dissolution of surface iron from the steel strip is substantially eliminated, improving the stannous ion plating solution quality, eliminating requirements for harmful additives, and increasing the variety of electrolytically tinplated continuous-strip steel products and processes.