25 K V 50 Hz - Overview

Overview

This electrification is ideal for railways that cover long distances and/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 why it was not introduced earlier was the increased clearance distances required where it ran under bridges and in tunnels. Another reason was the lack of suitable control and rectification equipment before the development of solid-state rectifiers and related technology.

Railways using older, lower-capacity direct current systems such as France, Russia, South Africa, Spain, Italy, Belgium, Slovakia and The Netherlands have introduced or are introducing 25 kV AC instead of 3 kV DC/1.5 kV DC for their new high-speed lines.

The Channel Tunnel uses 25 kV, 50 Hz.