Past and present of electric traction

The beginning of electric traction dates back to 1879. It was during Berlin Trades Exposition in 1879 that Werner von Siemens built and showed first passenger electric railway driven with direct current motor supplied from 600 V dc traction network. Since then electric traction has been undergoing continuous development. The successive stages of locomotive drive systems and supply systems evolution may be enumerated as follows: - locomotive three-phase induction slip-ring motor drive, supplied directly from 3.3 kV, 16 2/3 Hz three-phase network - locomotive one-phase ac motor drive, supplied via one-phase transformer located in the locomotive, one-phase, 15 kV, 16 2/3 Hz traction network - locomotive dc series motors drive, 3 kV dc network - locomotive induction cage motor drive, traction network varies from country to country (3 kV dc, 15 kV ac, 20 kV ac, 25 kV ac). The magnetic railway is the most current achievement in electric traction