The electrification of the rail network
Just before the Second World War, a minor part of the French rail network (3,350 kilometres) was supplied with electricity.
Electricity turned out to be a mastercard for the future improvement of railways since France did not have much coal in its soil.
The first high-speed realizations, on a large scale, are the "Tokkaïdo train" in Japan and the TGV train in France. They are both supplied with single-phase AC current (50 Hz in frequency).
The United States and Germany were the first countries to use electricity as a source of energy.
Thomas Edison, in the United States, firstly worked on DC current produced by the General Electric company. In Europe,
The industrial use of AC current was patented by the American company, Westinghouse. Its first realization : New York - new Haven in 1905.
In Germany, AEG invented the three-phase synchronous drive which confirmed that electricity should enable trains to move very quickly. In October 1905, two railcars made by AEG and Siemens reached 210 kph (a world speed record at that time).
However, the Öerlikon and Brown - Boveri (in Germany and Switzerland) companies promoted the use of single-phase current to supply locomotives.
On August 29, 1920, the French government chose DC current (1,500 V) for all the French rail network.
Currently, in France, the frequency is 50 Hz whereas in Japan, the frequency is 60 Hz (in the United States as well).
The German ICE train is supplied with AC current (162/3 Hz in frequency).