25 kV AC railway electrification

Standard current and voltage settings for most high-speed rail Railway electrification systems used in Europe: Non-electrified 750 V DC 1.5 kV DC 3 kV DC 15 kV AC 25 kV AC High-speed lines in France, Spain, Italy, the Netherlands, Belgium and the United Kingdom operate under 25 kV, as do high power lines in the former Soviet Union. Railway electrification systems using alternating current (AC) at 25 kilovolts (kV) are used worldwide, especially for high-speed rail. It is usually supplied at the standard utility frequency (typically 50 or 60 Hz), which simplifies traction substations. The development of 25 kV AC electrification is closely connected with that of successfully using utility frequency. The East Coast Main Line in the United Kingdom is electrified using 25 kV 50 Hz overhead lines. This electrification is ideal for railways that cover long distances or carry heavy traffic. After some experimentation before World War II in Hungary and in the Black Forest in Germany, it came into widespread use in the 1950s. One of the reasons it was not introduced earlier was the lack of suitable small and lightweight control and rectification equipment before the development of solid-stat