Werner von Siemens, ennobled in 1888, developed an electric generator, based on the dynamo-electric principle, which he patented in 1866.
On January 17, 1867, he gave a lecture before the Berlin Academy of Sciences, in which he provided the first scientific description of the dynamo-electric principle.
However, the proposed design from July 1878, which aimed to drive the locomotive with two rubber discs on an iron band in the center, and subsequent adjustments did not convince the mine owner Carl Westphal.
Based on a design from October 1878, a locomotive was built to be presented to the public at the Berlin Trade Exhibition 1879.
[7] The locomotive was operated with a direct current of 150 V. The electrical energy was transmitted via the two rails and an insulated iron band positioned in between.