On DC railroads, the contact rail is used as a return conductor for the traction current. The rail is insulated against the ground, this insulation can be defective due to age or external influences. The resulting “fault” currents are dangerous for people and buildings.
The applicable standard DIN EN 50122 describes how these must be monitored and treated accordingly when currents and voltages occur.
Our products take over this function and ensure compliance with 50122.