A method and system for automatically filling the narrow gap between facing end walls of adjacent first and second railway rails (12) by depositing vertically spaced layers of molten metal in the gap (g) with an electric arc welding torch (30) using a robotic mechanism (50) that moves the torch in a pattern controlled by a low level robotic execute program from a spatial position to a next spatial position, said method and system comprising: constructing a data array for a specific gap, said array constituting a series of positions making up an idealized progression of said torch to fill said gaps in vertically spaced layers made up of multiple positions, each of said fixed positions identified by at least four coordinates, including (1) at least x, y, and z, (2) the layer in which said position is a part and (3) the welding parameters to be executed while said torch moves toward the next position; outputting data relating to a specific position from said data array; processing said welding parameters associated with said outputted data using said robotic execute program; then, outputting the new fixed data relating to the next position in said series of points; processing said welding parameters associated with said new data using said robotic execute program; and, repeating said outputting and processing acts until said positions in said data array relating to a specific layer have been processed. Thereafter the method or system repeats the layer or processes the next layer comprising multiple stored positions.