The first electrified railway was exhibited at the Berlin Trade Fair in May 1879. This is an elliptical railway with a length of about 300m and a track gauge of1m. It is powered by an external DC power supply of 150V via the third track, with two tracks as track loops. The electric locomotive is only 945kg. Although the electrified railway is very short, it has laid the foundation for the electrified railway. electric railway

188 1 year, an electrified railway with a length of 2.45km was built in Licht Felder-Military College of Siemens, Germany. In the same year, the first 500-meter-long tram line powered by overhead conductors appeared in London, France, and was officially put into commercial operation on 1885.

Ac power supply cycle

1903, a three-phase AC electric locomotive powered by three overhead lines appeared in Hungary, but it stopped soon, mainly because it was too difficult to maintain. 1932, Hungary successfully adopted 16kV power frequency single-phase alternating current on electrified railways for the first time. 1950 France built a 25KV single-phase power frequency experimental line through research and demonstration. 1953 25KV80Hz single-phase AC system was applied to the southeast line, and good economic benefits were obtained.