Steel frame resembling a railroad bogie with two axles; the electric motor is mounted around the axle of the larger wheel. The motor consists of an inner wooden fixed wheel made up of two rings, each carrying ten electromagnets facing outward. A similar wheel, concentric to the first, rotates and carries the electromagnets facing inward so that the poles move over one another. Two sets of brass strips on the outer wheel rub against the strips of the brass commutator placed on the rim of the inner fixed wheel and are connected to the electromagnets. In this way, the inner electromagnets are energized in sequence, turning the wheel and so moving the bogie forward. Made by Tecnomasio Italiano. Experiments on electric traction began in the late nineteenth century, but electric locomotives did not begin to replace steam locomotives until the twentieth century.