For Direct Current (DC) Railways Witt IndustrieElektronik develops and implements a wide range of protective and measurement systems.

Operating DC railways there is always the risk that unacceptable high contact voltages evolve – typically between rolling assets and the infrastructure like bridges or platforms occur. The Witt IndustrieElektronik product family for this field measures the voltages and initiates further actions.

One example is a development of a shirt circuiting device (ESC) developed for the Berlin Metro. This protects passengers from harmful contact voltages and the metro assets against corrosion because of stray currents. The newest development of this device conforms with the recent version of the European norm EN 50122.

All systems were developed together with Deutsche Bahn or Berlin Public Transport System BVG.

If you want to learn more about our products: Please download the brochure about our DC systems:


Earth Potential Meter EPM

While operating DC railways with running rails as return conductor, various ground resistances generate voltages that might be dangerous for humans or buildings. One of the measures to protect humans from impermissible… Continued

Earth Short Circuiting Device ESC

Direct connection between the return conductor and the earth has to be prevented within DC traction systems due to the risk of stray currents as stray currents would lead to corrosion of… Continued

Transducer TD

The transducers of Witt enable a very accurate measurement of driving voltages and currents in electrical isolation.

The transducers are used in DC-powered vehicles as well as in stationary facilities. The… Continued

Voltage Limiter VL

On DC railways, the immediate connection of the return conductors to the ground has to be prevented because hazardous stray currents may occur. Stray currents could damage buildings, bridges and other metallic… Continued

Potential Monitoring Device PMD

The potential monitoring device PMD measures the difference of the electric potentials between two measurement points. If a pre-set value is exceeded the device is short-circuiting those two potentials temporarily… Continued

Potential and Stray Current Monitoring

In a rail system powered by DC unwanted electric potentials and stray currents can occur because typically the running rail is used as a return conductor. Due to unavoidable isolation issues of… Continued